Doing a WHERE IN on multiple columns in Postgresql

Question

I have a table \'answers\' with an indexed \'problem_id\' integer column, a \'times_chosen\' integer column, and an \'option\' column that\'s a varchar. Currently the only v

Answer 1

You can do this if you cast the data to an array first:

UPDATE answers
SET times_chosen = times_chosen + 1
WHERE ARRAY[problem_id::VARCHAR,option] IN ('{4509,B}', '{622,C}', ... )

However, this will be incredibly inefficient, as it cannot use indexes. Using a JOIN as suggested by @Frank Farmer is a far better solution:

UPDATE answers a
SET times_chosen = times_chosen + 1
FROM (VALUES (4509,'B'), (622,'C') ...) AS x (id,o)
    WHERE x.id=a.problem_id AND x.o=a.option;

Answer 2

You can join against a virtual table of sorts:

SELECT * FROM answers
JOIN (VALUES (4509, 'B'), (622, 'C'), (1066, 'D'), (4059, 'A'), (4740, 'A')) 
    AS t (p,o)
ON p = problem_id AND o = option

You can do something similar with UPDATE.

Answer 3

You're probably looking for the

SELECT * FROM foo, bar WHERE foo.bob = "NaN" AND bar.alice = "Kentucky";

style syntax. Essentially, you use tablename.rowname to specify what individual field you're looking for. In order to line everything up properly, you add WHERE clauses that make sure the primary keys match:

...WHERE foo.primarykey = bar.primarykey

or similar. You'd do well to look up inner joins.

Answer 4

It should, at least I've done it before in other SQLs.

Have you tried it? You can test it with SET times_chosen = times_chosen