Re: [SQL] Using intersect in subquery - Mailing list pgsql-sql

From Tom Lane
Subject Re: [SQL] Using intersect in subquery
Date
Msg-id 24554.934984289@sss.pgh.pa.us
Whole thread Raw
In response to Re: [SQL] Using intersect in subquery  (Bruce Momjian <maillist@candle.pha.pa.us>)
Responses Re: [SQL] Using intersect in subquery  (Herouth Maoz <herouth@oumail.openu.ac.il>)
Re: [SQL] Using intersect in subquery  (Bruce Momjian <maillist@candle.pha.pa.us>)
List pgsql-sql
Bruce Momjian <maillist@candle.pha.pa.us> writes:
> Try 6.5.  We fixed some Intersect stuff.
>> 
>> select * from Table1
>> where KeyField1 in
>> (select KeyField2 from Table2 where  somecondition
>> intersect
>> select KeyField3 from Table3  where somecondition);
>> 
>> (I believe) I am running PG 6.4.  The INTERSECT by itself works, but not in
>> a subquery.
>> 

No, it still won't work --- the current grammar specifies SubSelect not
select_clause as the kind of select you can put inside an expression.
Not sure what it would take to fix this; I have a feeling that just
changing the grammar wouldn't be good enough :-(.  Better add it to the
TODO list:* Support UNION/INTERSECT/EXCEPT in sub-selects
        regards, tom lane


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