database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-30 11:03:19 +03:00
Code Activity

Add SQL Standard WITH ORDINALITY support for UNNEST (and any other SRF)

Browse Source 
Author: Andrew Gierth, David Fetter
Reviewers: Dean Rasheed, Jeevan Chalke, Stephen Frost
This commit is contained in:
Greg Stark
2013-07-29 16:38:01 +01:00
parent 55cbfa5366
commit c62736cc37
22 changed files with 1486 additions and 323 deletions
Download Patch File Download Diff File Expand all files Collapse all files

44
doc/src/sgml/func.sgml
View File

@ -13278,7 +13278,7 @@ select $1[i][j]
generate_subscripts($1,2) g2(j);
$$ LANGUAGE sql IMMUTABLE;
CREATE FUNCTION
postgres=# SELECT * FROM unnest2(ARRAY[[1,2],[3,4]]);
SELECT * FROM unnest2(ARRAY[[1,2],[3,4]]);
unnest2
---------
1
@ -13286,6 +13286,48 @@ postgres=# SELECT * FROM unnest2(ARRAY[[1,2],[3,4]]);
3
4
(4 rows)
</programlisting>
</para>
<indexterm>
<primary>ordinality</primary>
</indexterm>
<para>
When a function in the <literal>FROM</literal> clause is suffixed by
<literal>WITH ORDINALITY</literal>, a <type>bigint</type> column is appended
to the output which starts from 1 and increments by 1 for each row of the
function's output. This is most useful in the case of set returning functions
such as UNNEST(). This functionality is available for functions returning
composite types or using <literal>OUT</literal> parameters, but not when using
a function returning <literal>RECORD</literal> with an explicit column
definition list.
<programlisting>
-- set returning function WITH ORDINALITY
SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
ls | n
-----------------+----
pg_serial | 1
pg_twophase | 2
postmaster.opts | 3
pg_notify | 4
postgresql.conf | 5
pg_tblspc | 6
logfile | 7
base | 8
postmaster.pid | 9
pg_ident.conf | 10
global | 11
pg_clog | 12
pg_snapshots | 13
pg_multixact | 14
PG_VERSION | 15
pg_xlog | 16
pg_hba.conf | 17
pg_stat_tmp | 18
pg_subtrans | 19
(19 rows)
</programlisting>
</para>

47
doc/src/sgml/ref/select.sgml
View File

@ -52,7 +52,8 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="parameter">expression</replac
[ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ] [ [ AS ] <replaceable class="parameter">alias</replaceable> [ ( <replaceable class="parameter">column_alias</replaceable> [, ...] ) ] ]
[ LATERAL ] ( <replaceable class="parameter">select</replaceable> ) [ AS ] <replaceable class="parameter">alias</replaceable> [ ( <replaceable class="parameter">column_alias</replaceable> [, ...] ) ]
<replaceable class="parameter">with_query_name</replaceable> [ [ AS ] <replaceable class="parameter">alias</replaceable> [ ( <replaceable class="parameter">column_alias</replaceable> [, ...] ) ] ]
[ LATERAL ] <replaceable class="parameter">function_name</replaceable> ( [ <replaceable class="parameter">argument</replaceable> [, ...] ] ) [ AS ] <replaceable class="parameter">alias</replaceable> [ ( <replaceable class="parameter">column_alias</replaceable> [, ...] | <replaceable class="parameter">column_definition</replaceable> [, ...] ) ]
[ LATERAL ] <replaceable class="parameter">function_name</replaceable> ( [ <replaceable class="parameter">argument</replaceable> [, ...] ] ) [ WITH ORDINALITY ] [ [ AS ] <replaceable class="parameter">alias</replaceable> [ ( <replaceable class="parameter">column_alias</replaceable> [, ...] ) ] ]
[ LATERAL ] <replaceable class="parameter">function_name</replaceable> ( [ <replaceable class="parameter">argument</replaceable> [, ...] ] ) [ AS ] <replaceable class="parameter">alias</replaceable> ( <replaceable class="parameter">column_definition</replaceable> [, ...] )
[ LATERAL ] <replaceable class="parameter">function_name</replaceable> ( [ <replaceable class="parameter">argument</replaceable> [, ...] ] ) AS ( <replaceable class="parameter">column_definition</replaceable> [, ...] )
<replaceable class="parameter">from_item</replaceable> [ NATURAL ] <replaceable class="parameter">join_type</replaceable> <replaceable class="parameter">from_item</replaceable> [ ON <replaceable class="parameter">join_condition</replaceable> | USING ( <replaceable class="parameter">join_column</replaceable> [, ...] ) ]
@ -368,18 +369,40 @@ TABLE [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ]
clause. (This is especially useful for functions that return
result sets, but any function can be used.) This acts as
though its output were created as a temporary table for the
duration of this single <command>SELECT</command> command. An
alias can also be used. If an alias is written, a column alias
list can also be written to provide substitute names for one
or more attributes of the function's composite return type. If
the function has been defined as returning the <type>record</>
data type, then an alias or the key word <literal>AS</> must
be present, followed by a column definition list in the form
<literal>( <replaceable
duration of this single <command>SELECT</command> command.
When the optional <command>WITH ORDINALITY</command> is
appended to the function call, a new column is appended after
all the function call's columns with numbering for each row.
For example:
<programlisting>
SELECT * FROM unnest(ARRAY['a','b','c','d','e','f']) WITH ORDINALITY;
unnest | ordinality
--------+----------
a | 1
b | 2
c | 3
d | 4
e | 5
f | 6
(6 rows)
</programlisting>
An alias can also be used. If an alias is written, a column
alias list can also be written to provide substitute names for
one or more attributes of the function's composite return
type, including the column added by <literal>ORDINALITY</literal>
if present.
</para>
<para>
If the function has been defined as returning the
<type>record</> data type, then an alias or the key word
<literal>AS</> must be present, followed by a column
definition list in the form <literal>( <replaceable
class="parameter">column_name</replaceable> <replaceable
class="parameter">data_type</replaceable> <optional>, ... </>
)</literal>. The column definition list must match the actual
number and types of columns returned by the function.
class="parameter">data_type</replaceable> <optional>, ...
</>)</literal>. The column definition list must match the
actual number and types of columns returned by the function.
<literal>ORDINALITY</literal> does not work in this case.
</para>
</listitem>
</varlistentry>