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Thanks Mark! Excellent! That's what I'm talking about!

On 11/23/2022 2:18 AM, Mark Waterbury wrote:

You should NOT do a "SELECT * ..." if you want better performance.

You can do this "existence" checking like this:

            FETCH FIRST 1 ROWS ONLY )

I learned this trick from this article:

Even though it is not specific to Db2i, it is for "Db2" ... interesting to learn how improving the performance of such "existence" checks has improved over the years.

Hope that helps ...

Mark S. Waterbury

On Tuesday, November 22, 2022 at 03:50:24 PM EST, Alan Cassidy <cfuture@xxxxxxxxxxx> wrote:

SQL references gives an example of EXISTS:


I would assume that the search in file EMPLOYEE stops when it finds the
first instance of a row that matches.

Is that so?

I'm asking because I'm modifying a program that has a /very/ /heavy/
performance burden, and I have to squeeze milliseconds out of it
anywhere I can get it.

--Alan Cassidy

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