This is normaol behavior.
> I belive that I have found a bug - or maybe it was done on purpose. Have
> a look at this query:
>
>
> SELECT integer_field FROM bugtable WHERE (CASE WHEN '' <> '' THEN
> integer_field = '' ELSE integer_field = 0 END);
> Result: ERROR: invalid input syntax for integer: ""
Here CASE have int type and you are trying to cast '' to int. Error.
>
>
> SELECT text_field FROM bugtable WHERE (CASE WHEN '' <> '' THEN
> text_field = '' ELSE text_field = '1' END);
> Result: 1 rows fetched (0,02 sec)
Here CASE have text type. Everything is fine.
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
