On Thu, Aug 25, 2005 at 09:53:26AM +0100, THIBAULT Jean-Jacques wrote: > > this query work : > select null UNION 1;
Please show the *exact* query. The above produces a syntax error: test=> select null UNION 1; ERROR: syntax error at or near "1" at character 19 LINE 1: select null UNION 1; ^ I suspect this is the actual query: test=> select null UNION select 1; ?column? ---------- 1 (2 rows) > this query doesn't work : > select null UNION null UNION 1; > > ERROR: UNION types text and integer cannot be matched Again, the query as written causes a syntax error. This is probably the actual query: test=> select null UNION select null UNION select 1; ERROR: UNION types text and integer cannot be matched To understand what's happening, see "UNION, CASE, and ARRAY Type Resolution" in the "Type Conversion" chapter of the documentation: http://www.postgresql.org/docs/8.0/static/typeconv-union-case.html -- Michael Fuhr ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster