Haven't checked this, so.........
SELECT COUNT(DISTINCT(master.id)) FROM master, a, b WHERE master.id=a.id OR
master.id=b.id;
Tomy.
-----Original Message-----
From: Kelly Yancey <kbyanc@stripped>
To: mysql@stripped <mysql@stripped>
Date: èetvrtak, travanj 22, 1999 17:23
Subject: Question: how to count unique rows in multiple tables?
>
> I've run into a deceptively simple problem: I have 2 tables each which
>are associated with a 3rd table via an ID field, I need to count the
>number of rows with unique ID values in both of the 2 tables. For example:
>
> Master Table
> ID Name
> --------------------------
> 0 Example
> 1 Another example
> 2 One more example
> 3 Final example
>
> Table A
> ID Data
> -------------------------
> 0 Some associated data
> 0 Another piece of data
> 3 Yet more data
>
> Table B
> ID OtherData
> ------------------------
> 0 Stuff
> 1 More Stuff
> 1 Even More Stuff
>
> What I would be looking for is the number of rows with unique ID values
>between Table A and Table B (so the answer should be 3: (IDs 0, 1, and 3))
>How would I do this with a SQL query?
>
> I really appreciate the help!
>
> Kelly
>
> ~kbyanc@stripped~
> "Silly penguin, Linux is for kids"
>
>
>
>
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