Sean,

S> Firebird currently has no function to parse the SQL and recognize that

S> ... where exists (select * from some_table where ..., or
S> ... where exists (select somefield from some_table where ....

S> are bad and should be replaced with

S> ... where exists (select 1 from some_table where...

I guess that Sasha's point was that it's not clear why the first two
are bad and the third is good. I for one use the third form myself
always, but I do that mainly for better code readability (as in:
always make it clear whether your goal is to select something or just
to see if anything's there). I wouldn't expect any noticeable
difference in performance (outside of the parser) among the three.

Ciao
--
Nando Dessena
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