WHERE col1,col2 IN (...) [SQL subquery using composite primary key]

Question

Given a table foo with a composite primary key (a,b), is there a legal syntax for writing a query such as:

SELECT ... FROM foo WHERE a,b IN (SELECT ...many tuples of a/b values...);
UPDATE foo SET ... WHERE a,b IN (SELECT ...many tuples of a/b values...);

If this is not possible, and you could not modify the schema, how could you perform the equivalent of the above?

I'm also going to put the terms "compound primary key", "subselect", "sub-select", and "sub-query" here for search hits on these aliases.

Edit: I'm interested in answers for standard SQL as well as those that would work with PostgreSQL and SQLite 3.

Answer 1

sqlite> create table foo (a,b,c);
sqlite> create table bar (x,y);
sqlite> select * from foo where exists (select 1 from bar where foo.a = bar.x and foo.b = bar.y);

Replace the select 1 from bar with your select ... many tuples of a/b values ....

Or create a temporary table of your select ... many tuples of a/b values ... and use it in place of bar..