database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-12-10 14:22:35 +03:00
Code Activity

Reimplementation of UNION/INTERSECT/EXCEPT. INTERSECT/EXCEPT now meet the

Browse Source 
SQL92 semantics, including support for ALL option.  All three can be used
in subqueries and views.  DISTINCT and ORDER BY work now in views, too.
This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
where the SELECT yields different datatypes than the INSERT needs.  I did
that by making UNION subqueries and SELECT in INSERT be treated like
subselects-in-FROM, thereby allowing an extra level of targetlist where the
datatype conversions can be inserted safely.
INITDB NEEDED!
This commit is contained in:
Tom Lane
2000-10-05 19:11:39 +00:00
parent 5292637f52
commit 05e3d0ee86
51 changed files with 2621 additions and 1935 deletions
Download Patch File Download Diff File Expand all files Collapse all files

85
src/test/regress/expected/union.out
View File

@@ -1,5 +1,5 @@
--
-- UNION
-- UNION (also INTERSECT, EXCEPT)
--
-- Simple UNION constructs
SELECT 1 AS two UNION SELECT 2;
@@ -71,10 +71,10 @@ SELECT 1 AS two UNION SELECT 2.2;
two
-----
1
2
2.2
(2 rows)
SELECT 1 AS one UNION SELECT 1.1;
SELECT 1 AS one UNION SELECT 1.0;
one
-----
1
@@ -87,36 +87,43 @@ SELECT 1.1 AS two UNION ALL SELECT 2;
2
(2 rows)
SELECT 1 AS two UNION ALL SELECT 1;
SELECT 1.0 AS two UNION ALL SELECT 1;
two
-----
1
1
(2 rows)
SELECT 1 AS three UNION SELECT 2 UNION SELECT 3;
SELECT 1.1 AS three UNION SELECT 2 UNION SELECT 3;
three
-------
1
1.1
2
3
(3 rows)
SELECT 1 AS two UNION SELECT 2 UNION SELECT 2;
SELECT 1.1 AS two UNION SELECT 2 UNION SELECT 2.0;
two
-----
1
1.1
2
(2 rows)
SELECT 1 AS three UNION SELECT 2 UNION ALL SELECT 2;
SELECT 1.1 AS three UNION SELECT 2 UNION ALL SELECT 2;
three
-------
1
1.1
2
2
(3 rows)
SELECT 1.1 AS two UNION (SELECT 2 UNION ALL SELECT 2);
two
-----
1.1
2
(2 rows)
--
-- Try testing from tables...
--
@@ -247,3 +254,61 @@ SELECT TRIM(TRAILING FROM f1) FROM CHAR_TBL;
hi de ho neighbor
(5 rows)
--
-- INTERSECT and EXCEPT
--
SELECT q2 FROM int8_tbl INTERSECT SELECT q1 FROM int8_tbl;
q2
------------------
123
4567890123456789
(2 rows)
SELECT q2 FROM int8_tbl INTERSECT ALL SELECT q1 FROM int8_tbl;
q2
------------------
123
4567890123456789
4567890123456789
(3 rows)
SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl;
q2
-------------------
-4567890123456789
456
(2 rows)
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl;
q2
-------------------
-4567890123456789
456
(2 rows)
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q1 FROM int8_tbl;
q2
-------------------
-4567890123456789
456
4567890123456789
(3 rows)
--
-- Mixed types
--
SELECT f1 FROM float8_tbl INTERSECT SELECT f1 FROM int4_tbl;
f1
----
0
(1 row)
SELECT f1 FROM float8_tbl EXCEPT SELECT f1 FROM int4_tbl;
f1
-----------------------
-1.2345678901234e+200
-1004.3
-34.84
-1.2345678901234e-200
(4 rows)

35
src/test/regress/sql/union.sql
View File

@@ -1,5 +1,5 @@
--
-- UNION
-- UNION (also INTERSECT, EXCEPT)
--
-- Simple UNION constructs
@@ -26,17 +26,19 @@ SELECT 1.1 AS two UNION SELECT 2;
SELECT 1 AS two UNION SELECT 2.2;
SELECT 1 AS one UNION SELECT 1.1;
SELECT 1 AS one UNION SELECT 1.0;
SELECT 1.1 AS two UNION ALL SELECT 2;
SELECT 1 AS two UNION ALL SELECT 1;
SELECT 1.0 AS two UNION ALL SELECT 1;
SELECT 1 AS three UNION SELECT 2 UNION SELECT 3;
SELECT 1.1 AS three UNION SELECT 2 UNION SELECT 3;
SELECT 1 AS two UNION SELECT 2 UNION SELECT 2;
SELECT 1.1 AS two UNION SELECT 2 UNION SELECT 2.0;
SELECT 1 AS three UNION SELECT 2 UNION ALL SELECT 2;
SELECT 1.1 AS three UNION SELECT 2 UNION ALL SELECT 2;
SELECT 1.1 AS two UNION (SELECT 2 UNION ALL SELECT 2);
--
-- Try testing from tables...
@@ -82,3 +84,24 @@ SELECT f1 FROM VARCHAR_TBL
UNION
SELECT TRIM(TRAILING FROM f1) FROM CHAR_TBL;
--
-- INTERSECT and EXCEPT
--
SELECT q2 FROM int8_tbl INTERSECT SELECT q1 FROM int8_tbl;
SELECT q2 FROM int8_tbl INTERSECT ALL SELECT q1 FROM int8_tbl;
SELECT q2 FROM int8_tbl EXCEPT SELECT q1 FROM int8_tbl;
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT q1 FROM int8_tbl;
SELECT q2 FROM int8_tbl EXCEPT ALL SELECT DISTINCT q1 FROM int8_tbl;
--
-- Mixed types
--
SELECT f1 FROM float8_tbl INTERSECT SELECT f1 FROM int4_tbl;
SELECT f1 FROM float8_tbl EXCEPT SELECT f1 FROM int4_tbl;