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7517d7e112
"Process NATURAL and USING joins according to SQL:2003".
* Some of the main problems fixed by the patch:
- in "select *" queries the * expanded correctly according to
ANSI for arbitrary natural/using joins
- natural/using joins are correctly transformed into JOIN ... ON
for any number/nesting of the joins.
- column references are correctly resolved against natural joins
of any nesting and combined with arbitrary other joins.
* This patch also contains a fix for name resolution of items
inside the ON condition of JOIN ... ON - in this case items must
be resolved only against the JOIN operands. To support such
'local' name resolution, the patch introduces a stack of
name resolution contexts used at parse time.
NOTICE:
- This patch is not complete in the sense that
- there are 2 test cases that still do not pass -
one in join.test, one in select.test. Both are marked
with a comment "TODO: WL#2486".
- it does not include a new test specific for the task
mysql-test/include/ps_query.inc:
Adjusted according to standard NATURAL/USING join semantics.,
mysql-test/r/bdb.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/derived.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/errors.result:
The column as a whole cannot be resolved, so different error message.
mysql-test/r/fulltext.result:
Adjusted according to standard JOIN ... ON semantics =>
the ON condition can refer only to the join operands.
mysql-test/r/fulltext_order_by.result:
More detailed error message.
mysql-test/r/innodb.result:
Adjusted according to standard NATURAL/USING join semantics.
This test doesn't pass completetly yet!
mysql-test/r/insert_select.result:
More detailed error message.
mysql-test/r/join.result:
Adjusted according to standard NATURAL/USING join semantics.
NOTICE: there is one test case that still fails, and it is
commeted out and marked with WL#2486 in the test file.
mysql-test/r/join_crash.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/join_nested.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/join_outer.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/multi_update.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/null_key.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/order_by.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_2myisam.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_3innodb.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_4heap.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_5merge.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_6bdb.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/ps_7ndb.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/select.result:
Adjusted according to standard NATURAL/USING join semantics.
NOTICE: there is one failing test case which is commented with
WL#2486 in the test file.
mysql-test/r/subselect.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/type_ranges.result:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/r/union.result:
More detailed error message.
mysql-test/t/bdb.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/errors.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/fulltext.test:
Adjusted according to standard JOIN ... ON semantics =>
the ON condition can refer only to the join operands.
mysql-test/t/fulltext_order_by.test:
More detailed error message.
mysql-test/t/innodb.test:
Adjusted according to standard NATURAL/USING join semantics.
This test doesn't pass completetly yet!
mysql-test/t/insert_select.test:
More detailed error message.
mysql-test/t/join.test:
Adjusted according to standard NATURAL/USING join semantics.
NOTICE: there is one test case that still fails, and it is
commeted out and marked with WL#2486 in the test file.
mysql-test/t/join_crash.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/join_nested.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/join_outer.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/null_key.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/order_by.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/select.test:
Adjusted according to standard NATURAL/USING join semantics.
NOTICE: there is one test case that still fails, and it is
commeted out and marked with WL#2486 in the test file.
mysql-test/t/subselect.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/type_ranges.test:
Adjusted according to standard NATURAL/USING join semantics.
mysql-test/t/union.test:
More detailed error message.
sql/item.cc:
- extra parameter to find_field_in_tables
- find_field_in_real_table renamed to find_field_in_table
- fixed comments/typos
sql/item.h:
- added [first | last]_name_resolution_table to class
Name_resolution_context
- commented old code
- standardized formatting
sql/mysql_priv.h:
- refactored the find_field_in_XXX procedures,
- added a new procedure for natural join table references,
- renamed the find_field_in_XXX procedures to clearer names
sql/sp.cc:
- pass the top-most list of the FROM clause to setup_tables
- extra parameter to find_field_in_tables
sql/sql_acl.cc:
- renamed find_field_in_table => find_field_in_table_ref
- extra parameter to find_field_in_table_ref
- commented old code
sql/sql_base.cc:
This file contains the core of the implementation of the processing
of NATURAL/USING joins (WL#2486).
- added many comments to old code
- refactored the group of find_field_in_XXX procedures, and added a
new procedure for natural joins. There is one find_field_in_XXX procedure
per each type of table reference (stored table, merge view, or natural
join); one meta-procedure that selects the correct one depeneding on the
table reference; and one procedure that goes over a list of table
referenes.
- NATURAL/USING joins are processed through the procedures:
mark_common_columns, store_natural_using_join_columns,
store_top_level_join_columns, setup_natural_join_row_types.
The entry point to processing NATURAL/USING joins is the
procedure 'setup_natural_join_row_types'.
- Replaced the specialized Field_iterator_XXX iterators with one
generic iterator over the fields of a table reference.
- Simplified 'insert_fields' and 'setup_conds' due to encapsulation of
the processing of natural joins in a separate set of procedures.
sql/sql_class.h:
- Commented old code.
sql/sql_delete.cc:
- Pass the FROM clause to setup_tables.
sql/sql_help.cc:
- pass the end name resolution table to find_field_in_tables
- adjust the list of tables for name resolution
sql/sql_insert.cc:
- Changed the code that saves and restores the current context to
support the list of tables for name resolution -
context->first_name_resolution_table, and
table_list->next_name_resolution_table.
Needed to support an ugly trick to resolve inserted columns only in
the first table.
- Added Name_resolution_context::[first | last]_name_resolution_table.
- Commented old code
sql/sql_lex.cc:
- set select_lex.parent_lex correctly
- set correct state of the current name resolution context
sql/sql_lex.h:
- Added a stack of name resolution contexts to support local
contexts for JOIN ... ON conditions.
- Commented old code.
sql/sql_load.cc:
- Pass the FROM clause to setup_tables.
sql/sql_olap.cc:
- Pass the FROM clause to setup_tables.
sql/sql_parse.cc:
- correctly set SELECT_LEX::parent_lex
- set the first table of the current name resoltion context
- added support for NATURAL/USING joins
- commented old code
sql/sql_select.cc:
- Pass the FROM clause to setup_tables.
- Pass the end table to find_field_in_tables
- Improved comments
sql/sql_show.cc:
- Set SELECT_LEX::parent_lex.
sql/sql_update.cc:
- Pass the FROM clause to setup_tables.
sql/sql_yacc.yy:
- Added support for a stack of name resolution contexts needed to
implement name resolution for JOIN ... ON. A context is pushed
for each new JOIN ... ON, and popped afterwards.
- Added support for NATURAL/USING joins.
sql/table.cc:
- Added new class Natural_join_column to hide the heterogeneous
representation of column references for stored tables and for
views.
- Added a new list TABLE_LIST::next_name_resolution_table to
support name resolution with NATURAL/USING joins. Also added
other members to TABLE_LIST to support NATURAL/USING joins.
- Added a generic iterator over the fields of table references
of various types - class Field_iterator_table_ref
sql/table.h:
- Added new class Natural_join_column to hide the heterogeneous
representation of column references for stored tables and for
views.
- Added a new list TABLE_LIST::next_name_resolution_table to
support name resolution with NATURAL/USING joins. Also added
other members to TABLE_LIST to support NATURAL/USING joins.
- Added a generic iterator over the fields of table references
of various types - class Field_iterator_table_ref
tests/mysql_client_test.c:
Adjusted according to standard NATURAL JOIN syntax.
366 lines
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366 lines
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drop table if exists t1,t2,t3;
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select * from (select 2 from DUAL) b;
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2
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2
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SELECT 1 as a FROM (SELECT 1 UNION SELECT a) b;
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ERROR 42S22: Unknown column 'a' in 'field list'
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SELECT 1 as a FROM (SELECT a UNION SELECT 1) b;
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ERROR 42S22: Unknown column 'a' in 'field list'
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CREATE TABLE t1 (a int not null, b char (10) not null);
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insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
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CREATE TABLE t2 (a int not null, b char (10) not null);
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insert into t2 values (3,'c'),(4,'d'),(5,'f'),(6,'e');
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select t1.a,t3.y from t1,(select a as y from t2 where b='c') as t3 where t1.a = t3.y;
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a y
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3 3
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3 3
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select t1.a,t3.a from t1,(select * from t2 where b='c') as t3 where t1.a = t3.a;
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a a
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3 3
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3 3
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CREATE TABLE t3 (a int not null, b char (10) not null);
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insert into t3 values (3,'f'),(4,'y'),(5,'z'),(6,'c');
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select t1.a,t4.y from t1,(select t2.a as y from t2,(select t3.b from t3 where t3.a>3) as t5 where t2.b=t5.b) as t4 where t1.a = t4.y;
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a y
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3 3
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3 3
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SELECT a FROM (SELECT 1 FROM (SELECT 1) a HAVING a=1) b;
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ERROR 42S22: Unknown column 'a' in 'having clause'
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SELECT a,b as a FROM (SELECT '1' as a,'2' as b) b HAVING a=1;
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ERROR 23000: Column 'a' in having clause is ambiguous
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SELECT a,2 as a FROM (SELECT '1' as a) b HAVING a=2;
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a a
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1 2
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SELECT a,2 as a FROM (SELECT '1' as a) b HAVING a=1;
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a a
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SELECT 1 FROM (SELECT 1) a WHERE a=2;
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ERROR 42S22: Unknown column 'a' in 'where clause'
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SELECT (SELECT 1) as a FROM (SELECT 1 FROM t1 HAVING a=1) as a;
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ERROR 42S22: Unknown column 'a' in 'having clause'
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select * from t1 as x1, (select * from t1) as x2;
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a b a b
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1 a 1 a
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2 b 1 a
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3 c 1 a
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3 c 1 a
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1 a 2 b
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2 b 2 b
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3 c 2 b
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3 c 2 b
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1 a 3 c
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2 b 3 c
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3 c 3 c
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3 c 3 c
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1 a 3 c
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2 b 3 c
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3 c 3 c
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3 c 3 c
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explain select * from t1 as x1, (select * from t1) as x2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY x1 ALL NULL NULL NULL NULL 4
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4
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2 DERIVED t1 ALL NULL NULL NULL NULL 4
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drop table if exists t2,t3;
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select * from (select 1) as a;
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1
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1
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select a from (select 1 as a) as b;
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a
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1
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select 1 from (select 1) as a;
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1
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1
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select * from (select * from t1 union select * from t1) a;
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a b
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1 a
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2 b
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3 c
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select * from (select * from t1 union all select * from t1) a;
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a b
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1 a
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2 b
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3 c
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3 c
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1 a
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2 b
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3 c
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3 c
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select * from (select * from t1 union all select * from t1 limit 2) a;
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a b
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1 a
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2 b
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explain select * from (select * from t1 union select * from t1) a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3
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2 DERIVED t1 ALL NULL NULL NULL NULL 4
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3 UNION t1 ALL NULL NULL NULL NULL 4
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NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
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explain select * from (select * from t1 union all select * from t1) a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 8
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2 DERIVED t1 ALL NULL NULL NULL NULL 4
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3 UNION t1 ALL NULL NULL NULL NULL 4
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NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
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CREATE TABLE t2 (a int not null);
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insert into t2 values(1);
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select * from (select * from t1 where t1.a=(select a from t2 where t2.a=t1.a)) a;
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a b
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1 a
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select * from (select * from t1 where t1.a=(select t2.a from t2 where t2.a=t1.a) union select t1.a, t1.b from t1) a;
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a b
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1 a
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2 b
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3 c
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explain select * from (select * from t1,t2 where t1.a=t2.a) t1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY <derived2> system NULL NULL NULL NULL 1
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2 DERIVED t2 system NULL NULL NULL NULL 1
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2 DERIVED t1 ALL NULL NULL NULL NULL 4 Using where
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drop table t1, t2;
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create table t1(a int not null, t char(8), index(a));
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SELECT * FROM (SELECT * FROM t1) as b ORDER BY a ASC LIMIT 0,20;
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a t
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1 1
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2 2
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3 3
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4 4
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5 5
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6 6
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7 7
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8 8
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9 9
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10 10
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11 11
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12 12
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13 13
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14 14
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15 15
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16 16
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17 17
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18 18
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19 19
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20 20
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explain select count(*) from t1 as tt1, (select * from t1) as tt2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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2 DERIVED t1 ALL NULL NULL NULL NULL 10000
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drop table t1;
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SELECT * FROM (SELECT (SELECT * FROM (SELECT 1 as a) as a )) as b;
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(SELECT * FROM (SELECT 1 as a) as a )
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1
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select * from (select 1 as a) b left join (select 2 as a) c using(a);
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a
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1
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SELECT * FROM (SELECT 1 UNION SELECT a) b;
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ERROR 42S22: Unknown column 'a' in 'field list'
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SELECT 1 as a FROM (SELECT a UNION SELECT 1) b;
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ERROR 42S22: Unknown column 'a' in 'field list'
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SELECT 1 as a FROM (SELECT 1 UNION SELECT a) b;
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ERROR 42S22: Unknown column 'a' in 'field list'
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select 1 from (select 2) a order by 0;
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ERROR 42S22: Unknown column '0' in 'order clause'
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create table t1 (id int);
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insert into t1 values (1),(2),(3);
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describe select * from (select * from t1 group by id) bar;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3
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2 DERIVED t1 ALL NULL NULL NULL NULL 3 Using temporary; Using filesort
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drop table t1;
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create table t1 (mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, matintnum CHAR(6) NOT NULL, test MEDIUMINT UNSIGNED NULL);
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create table t2 (mat_id MEDIUMINT UNSIGNED NOT NULL, pla_id MEDIUMINT UNSIGNED NOT NULL);
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insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4), (NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8), (NULL, 'i', 9);
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insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
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SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
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pla_id mat_id
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100 1
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101 1
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102 1
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103 2
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104 2
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105 3
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SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
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pla_id test
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100 1
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101 1
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102 1
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103 2
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104 2
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105 3
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explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY m2 ALL NULL NULL NULL NULL 9
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using where
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2 DERIVED mp ALL NULL NULL NULL NULL 9 Using temporary; Using filesort
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2 DERIVED m1 eq_ref PRIMARY PRIMARY 3 test.mp.mat_id 1
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explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY m2 ALL NULL NULL NULL NULL 9
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using where
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2 DERIVED mp ALL NULL NULL NULL NULL 9 Using temporary; Using filesort
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2 DERIVED m1 eq_ref PRIMARY PRIMARY 3 test.mp.mat_id 1
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drop table t1,t2;
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SELECT a.x FROM (SELECT 1 AS x) AS a HAVING a.x = 1;
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x
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1
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create table t1 select 1 as a;
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select 2 as a from (select * from t1) b;
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ERROR 3D000: No database selected
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use test;
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select 2 as a from (select * from t1) b;
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a
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2
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drop table t1;
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select mail_id, if(folder.f_description!='', folder.f_description, folder.f_name) as folder_name, date, address_id, phrase, address, subject from folder, (select mail.mail_id as mail_id, date_format(mail.h_date, '%b %e, %Y %h:%i') as date, mail.folder_id, sender.address_id as address_id, sender.phrase as phrase, sender.address as address, mail.h_subject as subject from mail left join mxa as mxa_sender on mail.mail_id=mxa_sender.mail_id and mxa_sender.type='from' left join address as sender on mxa_sender.address_id=sender.address_id mxa as mxa_recipient, address as recipient, where 1 and mail.mail_id=mxa_recipient.mail_id and mxa_recipient.address_id=recipient.address_id and mxa_recipient.type='to' and match(sender.phrase, sender.address, sender.comment) against ('jeremy' in boolean mode) and match(recipient.phrase, recipient.address, recipient.comment) against ('monty' in boolean mode) order by mail.h_date desc limit 0, 25 ) as query where query.folder_id=folder.folder_id;
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ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'mxa as mxa_recipient, address as recipient, where 1 and mail.mail_id=mxa_r' at line 1
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create table t1 (a int);
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insert into t1 values (1),(2),(3);
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update (select * from t1) as t1 set a = 5;
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ERROR HY000: The target table t1 of the UPDATE is not updatable
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delete from (select * from t1);
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ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(select * from t1)' at line 1
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insert into (select * from t1) values (5);
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ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '(select * from t1) values (5)' at line 1
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drop table t1;
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create table t1 (E1 INTEGER UNSIGNED NOT NULL, E2 INTEGER UNSIGNED NOT NULL, E3 INTEGER UNSIGNED NOT NULL, PRIMARY KEY(E1)
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);
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insert into t1 VALUES(1,1,1), (2,2,1);
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select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
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count(*)
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2
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explain select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
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1 PRIMARY t1 eq_ref PRIMARY PRIMARY 4 THEMAX.E2 1 Using where
|
|
2 DERIVED A ALL NULL NULL NULL NULL 2 Using where
|
|
3 DEPENDENT SUBQUERY B ALL NULL NULL NULL NULL 2 Using where
|
|
drop table t1;
|
|
create table t1 (a int);
|
|
insert into t1 values (1),(2);
|
|
select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
|
|
a a
|
|
1 1
|
|
2 1
|
|
1 2
|
|
2 2
|
|
explain select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
|
|
1 PRIMARY <derived4> ALL NULL NULL NULL NULL 2
|
|
4 DERIVED t1 ALL NULL NULL NULL NULL 2
|
|
5 UNION t1 ALL NULL NULL NULL NULL 2
|
|
NULL UNION RESULT <union4,5> ALL NULL NULL NULL NULL NULL
|
|
2 DERIVED t1 ALL NULL NULL NULL NULL 2
|
|
3 UNION t1 ALL NULL NULL NULL NULL 2
|
|
NULL UNION RESULT <union2,3> ALL NULL NULL NULL NULL NULL
|
|
drop table t1;
|
|
CREATE TABLE `t1` (
|
|
`N` int(11) unsigned NOT NULL default '0',
|
|
`M` tinyint(1) default '0'
|
|
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
|
|
INSERT INTO `t1` (N, M) VALUES (1, 0),(1, 0),(1, 0),(2, 0),(2, 0),(3, 0);
|
|
UPDATE `t1` AS P1 INNER JOIN (SELECT N FROM `t1` GROUP BY N HAVING Count(M) > 1) AS P2 ON P1.N = P2.N SET P1.M = 2;
|
|
select * from t1;
|
|
N M
|
|
1 2
|
|
1 2
|
|
1 2
|
|
2 2
|
|
2 2
|
|
3 0
|
|
UPDATE `t1` AS P1 INNER JOIN (SELECT N FROM `t1` GROUP BY N HAVING Count(M) > 1) AS P2 ON P1.N = P2.N SET P1.M = 2, P2.N = 2;
|
|
ERROR HY000: The target table P2 of the UPDATE is not updatable
|
|
UPDATE `t1` AS P1 INNER JOIN (SELECT aaaa FROM `t1` GROUP BY N HAVING Count(M) > 1) AS P2 ON P1.N = P2.N SET P1.M = 2;
|
|
ERROR 42S22: Unknown column 'aaaa' in 'field list'
|
|
delete P1.* from `t1` AS P1 INNER JOIN (SELECT N FROM `t1` GROUP BY N HAVING Count(M) > 1) AS P2 ON P1.N = P2.N;
|
|
select * from t1;
|
|
N M
|
|
3 0
|
|
delete P1.*,p2.* from `t1` AS P1 INNER JOIN (SELECT N FROM `t1` GROUP BY N HAVING Count(M) > 1) AS p2 ON P1.N = p2.N;
|
|
ERROR HY000: The target table p2 of the DELETE is not updatable
|
|
delete P1.* from `t1` AS P1 INNER JOIN (SELECT aaa FROM `t1` GROUP BY N HAVING Count(M) > 1) AS P2 ON P1.N = P2.N;
|
|
ERROR 42S22: Unknown column 'aaa' in 'field list'
|
|
drop table t1;
|
|
CREATE TABLE t1 (
|
|
OBJECTID int(11) NOT NULL default '0',
|
|
SORTORDER int(11) NOT NULL auto_increment,
|
|
KEY t1_SortIndex (SORTORDER),
|
|
KEY t1_IdIndex (OBJECTID)
|
|
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
|
|
CREATE TABLE t2 (
|
|
ID int(11) default NULL,
|
|
PARID int(11) default NULL,
|
|
UNIQUE KEY t2_ID_IDX (ID),
|
|
KEY t2_PARID_IDX (PARID)
|
|
) engine=MyISAM DEFAULT CHARSET=latin1;
|
|
INSERT INTO t2 VALUES (1000,0),(1001,0),(1002,0),(1003,0),(1008,1),(1009,1),(1010,1),(1011,1),(1016,2);
|
|
CREATE TABLE t3 (
|
|
ID int(11) default NULL,
|
|
DATA decimal(10,2) default NULL,
|
|
UNIQUE KEY t3_ID_IDX (ID)
|
|
) engine=MyISAM DEFAULT CHARSET=latin1;
|
|
INSERT INTO t3 VALUES (1000,0.00),(1001,0.25),(1002,0.50),(1003,0.75),(1008,1.00),(1009,1.25),(1010,1.50),(1011,1.75);
|
|
select 497, TMP.ID, NULL from (select 497 as ID, MAX(t3.DATA) as DATA from t1 join t2 on (t1.ObjectID = t2.ID) join t3 on (t1.ObjectID = t3.ID) group by t2.ParID order by DATA DESC) as TMP;
|
|
497 ID NULL
|
|
drop table t1, t2, t3;
|
|
CREATE TABLE t1 (name char(1) default NULL, val int(5) default NULL);
|
|
INSERT INTO t1 VALUES ('a',1), ('a',2), ('a',2), ('a',2), ('a',3), ('a',6), ('a',7), ('a',11), ('a',11), ('a',12), ('a',13), ('a',13), ('a',20), ('b',2), ('b',3), ('b',4), ('b',5);
|
|
SELECT s.name, AVG(s.val) AS median FROM (SELECT x.name, x.val FROM t1 x, t1 y WHERE x.name=y.name GROUP BY x.name, x.val HAVING SUM(y.val <= x.val) >= COUNT(*)/2 AND SUM(y.val >= x.val) >= COUNT(*)/2) AS s GROUP BY s.name;
|
|
name median
|
|
a 7.0000
|
|
b 3.5000
|
|
explain SELECT s.name, AVG(s.val) AS median FROM (SELECT x.name, x.val FROM t1 x, t1 y WHERE x.name=y.name GROUP BY x.name, x.val HAVING SUM(y.val <= x.val) >= COUNT(*)/2 AND SUM(y.val >= x.val) >= COUNT(*)/2) AS s GROUP BY s.name;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3 Using temporary; Using filesort
|
|
2 DERIVED x ALL NULL NULL NULL NULL 17 Using temporary; Using filesort
|
|
2 DERIVED y ALL NULL NULL NULL NULL 17 Using where
|
|
drop table t1;
|
|
create table t2 (a int, b int, primary key (a));
|
|
insert into t2 values (1,7),(2,7);
|
|
explain select a from t2 where a>1;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 SIMPLE t2 index PRIMARY PRIMARY 4 NULL 2 Using where; Using index
|
|
explain select a from (select a from t2 where a>1) tt;
|
|
id select_type table type possible_keys key key_len ref rows Extra
|
|
1 PRIMARY <derived2> system NULL NULL NULL NULL 1
|
|
2 DERIVED t2 index PRIMARY PRIMARY 4 NULL 2 Using where; Using index
|
|
drop table t2;
|
|
CREATE TABLE `t1` ( `itemid` int(11) NOT NULL default '0', `grpid` varchar(15) NOT NULL default '', `vendor` int(11) NOT NULL default '0', `date_` date NOT NULL default '0000-00-00', `price` decimal(12,2) NOT NULL default '0.00', PRIMARY KEY (`itemid`,`grpid`,`vendor`,`date_`), KEY `itemid` (`itemid`,`vendor`), KEY `itemid_2` (`itemid`,`date_`));
|
|
insert into t1 values (128, 'rozn', 2, now(), 10),(128, 'rozn', 1, now(), 10);
|
|
SELECT MIN(price) min, MAX(price) max, AVG(price) avg FROM (SELECT SUBSTRING( MAX(concat(date_,";",price)), 12) price FROM t1 WHERE itemid=128 AND grpid='rozn' GROUP BY itemid, grpid, vendor) lastprices;
|
|
min max avg
|
|
10.00 10.00 10
|
|
DROP TABLE t1;
|
|
create table t1 (a integer, b integer);
|
|
insert into t1 values (1,4), (2,2),(2,2), (4,1),(4,1),(4,1),(4,1);
|
|
select distinct sum(b) from t1 group by a;
|
|
sum(b)
|
|
4
|
|
select distinct sum(b) from (select a,b from t1) y group by a;
|
|
sum(b)
|
|
4
|
|
drop table t1;
|
|
CREATE TABLE t1 (a char(10), b char(10));
|
|
INSERT INTO t1 VALUES ('root','localhost'), ('root','%');
|
|
SELECT * FROM (SELECT (SELECT a.a FROM t1 AS a WHERE a.a = b.a) FROM t1 AS b) AS c;
|
|
ERROR 21000: Subquery returns more than 1 row
|
|
DROP TABLE t1;
|
|
create table t1(a int);
|
|
create table t2(a int);
|
|
create table t3(a int);
|
|
insert into t1 values(1),(1);
|
|
insert into t2 values(2),(2);
|
|
insert into t3 values(3),(3);
|
|
select * from t1 union distinct select * from t2 union all select * from t3;
|
|
a
|
|
1
|
|
2
|
|
3
|
|
3
|
|
select * from (select * from t1 union distinct select * from t2 union all select * from t3) X;
|
|
a
|
|
1
|
|
2
|
|
3
|
|
3
|
|
drop table t1, t2, t3;
|