--
-- 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;
        q1        | ?column? 
------------------+----------
              123 |      0.4
 4567890123456789 |      0.6
(2 rows)

