postgresql/src/test/regress/sql/update.sql

--
-- UPDATE syntax tests
--

CREATE TABLE update_test (
    a   INT DEFAULT 10,
    b   INT,
    c   TEXT
);

INSERT INTO update_test VALUES (5, 10, 'foo');
INSERT INTO update_test(b, a) VALUES (15, 10);

SELECT * FROM update_test;

UPDATE update_test SET a = DEFAULT, b = DEFAULT;

SELECT * FROM update_test;

-- aliases for the UPDATE target table
UPDATE update_test AS t SET b = 10 WHERE t.a = 10;

SELECT * FROM update_test;

UPDATE update_test t SET b = t.b + 10 WHERE t.a = 10;

SELECT * FROM update_test;

--
-- Test VALUES in FROM
--

UPDATE update_test SET a=v.i FROM (VALUES(100, 20)) AS v(i, j)
  WHERE update_test.b = v.j;

SELECT * FROM update_test;

--
-- Test multiple-set-clause syntax
--

INSERT INTO update_test SELECT a,b+1,c FROM update_test;
SELECT * FROM update_test;

UPDATE update_test SET (c,b,a) = ('bugle', b+11, DEFAULT) WHERE c = 'foo';
SELECT * FROM update_test;
UPDATE update_test SET (c,b) = ('car', a+b), a = a + 1 WHERE a = 10;
SELECT * FROM update_test;
-- fail, multi assignment to same column:
UPDATE update_test SET (c,b) = ('car', a+b), b = a + 1 WHERE a = 10;

-- uncorrelated sub-select:
UPDATE update_test
  SET (b,a) = (select a,b from update_test where b = 41 and c = 'car')
  WHERE a = 100 AND b = 20;
SELECT * FROM update_test;
-- correlated sub-select:
UPDATE update_test o
  SET (b,a) = (select a+1,b from update_test i
               where i.a=o.a and i.b=o.b and i.c is not distinct from o.c);
SELECT * FROM update_test;
-- fail, multiple rows supplied:
UPDATE update_test SET (b,a) = (select a+1,b from update_test);
-- set to null if no rows supplied:
UPDATE update_test SET (b,a) = (select a+1,b from update_test where a = 1000)
  WHERE a = 11;
SELECT * FROM update_test;

-- if an alias for the target table is specified, don't allow references
-- to the original table name
UPDATE update_test AS t SET b = update_test.b + 10 WHERE t.a = 10;

-- Make sure that we can update to a TOASTed value.
UPDATE update_test SET c = repeat('x', 10000) WHERE c = 'car';
SELECT a, b, char_length(c) FROM update_test;

DROP TABLE update_test;