On Fri, Apr 13, 2012 at 11:59 AM, Jack Christensen <jackc@xxxxxxxxxxxxxxxxx> wrote: > On 4/13/2012 11:39 AM, Mike Blackwell wrote: >> >> Could someone please explain to me why the following select does not >> result in a syntax error? (9.0.3) >> >> begin; >> >> create table x( c1 integer , c2 integer); >> create table y( c3 integer, c4 integer); >> >> select * from x where c2 in ( select c2 from y where c4 = 2 ); >> >> >> rollback; >> >> Mike >> > Your subquery is correlated with the outer query. So the c2 in the subquery > is referring to table x. This is a good example of why one should always use a table alias prefix when using subqueries. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
