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|
--
-- SUBSELECT
--
SELECT 1 AS one WHERE 1 IN (SELECT 1);
one
-----
1
(1 row)
SELECT 1 AS zero WHERE 1 NOT IN (SELECT 1);
zero
------
(0 rows)
SELECT 1 AS zero WHERE 1 IN (SELECT 2);
zero
------
(0 rows)
-- Set up some simple test tables
CREATE TABLE SUBSELECT_TBL (
f1 integer,
f2 integer,
f3 float
);
INSERT INTO SUBSELECT_TBL VALUES (1, 2, 3);
INSERT INTO SUBSELECT_TBL VALUES (2, 3, 4);
INSERT INTO SUBSELECT_TBL VALUES (3, 4, 5);
INSERT INTO SUBSELECT_TBL VALUES (1, 1, 1);
INSERT INTO SUBSELECT_TBL VALUES (2, 2, 2);
INSERT INTO SUBSELECT_TBL VALUES (3, 3, 3);
INSERT INTO SUBSELECT_TBL VALUES (6, 7, 8);
INSERT INTO SUBSELECT_TBL VALUES (8, 9, NULL);
SELECT '' AS eight, * FROM SUBSELECT_TBL;
eight | f1 | f2 | f3
-------+----+----+----
| 1 | 2 | 3
| 2 | 3 | 4
| 3 | 4 | 5
| 1 | 1 | 1
| 2 | 2 | 2
| 3 | 3 | 3
| 6 | 7 | 8
| 8 | 9 |
(8 rows)
-- Uncorrelated subselects
SELECT '' AS two, f1 AS "Constant Select" FROM SUBSELECT_TBL
WHERE f1 IN (SELECT 1);
two | Constant Select
-----+-----------------
| 1
| 1
(2 rows)
SELECT '' AS six, f1 AS "Uncorrelated Field" FROM SUBSELECT_TBL
WHERE f1 IN (SELECT f2 FROM SUBSELECT_TBL);
six | Uncorrelated Field
-----+--------------------
| 1
| 2
| 3
| 1
| 2
| 3
(6 rows)
SELECT '' AS six, f1 AS "Uncorrelated Field" FROM SUBSELECT_TBL
WHERE f1 IN (SELECT f2 FROM SUBSELECT_TBL WHERE
f2 IN (SELECT f1 FROM SUBSELECT_TBL));
six | Uncorrelated Field
-----+--------------------
| 1
| 2
| 3
| 1
| 2
| 3
(6 rows)
SELECT '' AS three, f1, f2
FROM SUBSELECT_TBL
WHERE (f1, f2) NOT IN (SELECT f2, CAST(f3 AS int4) FROM SUBSELECT_TBL
WHERE f3 IS NOT NULL);
three | f1 | f2
-------+----+----
| 1 | 2
| 6 | 7
| 8 | 9
(3 rows)
-- Correlated subselects
SELECT '' AS six, f1 AS "Correlated Field", f2 AS "Second Field"
FROM SUBSELECT_TBL upper
WHERE f1 IN (SELECT f2 FROM SUBSELECT_TBL WHERE f1 = upper.f1);
six | Correlated Field | Second Field
-----+------------------+--------------
| 1 | 2
| 2 | 3
| 3 | 4
| 1 | 1
| 2 | 2
| 3 | 3
(6 rows)
SELECT '' AS six, f1 AS "Correlated Field", f3 AS "Second Field"
FROM SUBSELECT_TBL upper
WHERE f1 IN
(SELECT f2 FROM SUBSELECT_TBL WHERE CAST(upper.f2 AS float) = f3);
six | Correlated Field | Second Field
-----+------------------+--------------
| 2 | 4
| 3 | 5
| 1 | 1
| 2 | 2
| 3 | 3
(5 rows)
SELECT '' AS six, f1 AS "Correlated Field", f3 AS "Second Field"
FROM SUBSELECT_TBL upper
WHERE f3 IN (SELECT upper.f1 + f2 FROM SUBSELECT_TBL
WHERE f2 = CAST(f3 AS integer));
six | Correlated Field | Second Field
-----+------------------+--------------
| 1 | 3
| 2 | 4
| 3 | 5
| 6 | 8
(4 rows)
SELECT '' AS five, f1 AS "Correlated Field"
FROM SUBSELECT_TBL
WHERE (f1, f2) IN (SELECT f2, CAST(f3 AS int4) FROM SUBSELECT_TBL
WHERE f3 IS NOT NULL);
five | Correlated Field
------+------------------
| 2
| 3
| 1
| 2
| 3
(5 rows)
--
-- Use some existing tables in the regression test
--
SELECT '' AS eight, ss.f1 AS "Correlated Field", ss.f3 AS "Second Field"
FROM SUBSELECT_TBL ss
WHERE f1 NOT IN (SELECT f1+1 FROM INT4_TBL WHERE f1 != ss.f1);
eight | Correlated Field | Second Field
-------+------------------+--------------
| 2 | 4
| 3 | 5
| 2 | 2
| 3 | 3
| 6 | 8
| 8 |
(6 rows)
select q1, float8(count(*)) / (select count(*) from int8_tbl)
from int8_tbl group by q1 order by q1;
q1 | ?column?
------------------+----------
123 | 0.4
4567890123456789 | 0.6
(2 rows)
|
