Re: Query logic
Posted in 1996
Mickey Mestel — — source: Informix-list mailing list archive (1991-1998)
> From informix-list-owner@rmy.emory.edu Fri May 3 18:45:46 1996
> From: "Dave K. Lahoti" <D4kLaho@PacBell.COM>
> Subject: Query logic
dave,
> SELECT * FROM world
> WHERE 0 = 1;
the engine, (at least the 7.x engine that i am running) is smart
enough not to do this. i have a query like this that i use an input
parameter to decided which of two queries in a union is done.
you can go ahead an run this in isql and see. it should return
immediately with "no rows found". if it doesn't, then the engine is
actually doing the query, but i doubt you will see that.
mickm