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[Ilan Volow <listboy AT clarux.com>]

If you're trying to do "use this value, but use 0 instead if the value is null", you may want to substitute IF() with COALESCE(), which is more ANSI friendly (or so I've heard) and more portable between databases (theoretically). 

e,g, COALESCE(possibly_null_column_value, 0)

See http://dev.mysql.com/doc/refman/5.0/en/comparison-operators.html#function_coalesce

-- Ilan

On Feb 25, 2008, at 10:22 PM, Scott Russell wrote:

On Mon, 2008-02-25 at 18:47 -0500, Scott Russell wrote:

On Mon, 2008-02-25 at 16:41 -0500, Ilan Volow wrote:

I'm a PostgreSQL guy, so take my educated guess with a grain of salt,

but you might want to try this just to see if it works:

Much appreciated. I'll take a look at it...

FYI, You're suggestion worked fine. I'm not entirely convinced I'm doing

this sanely still, but it does work.

I also do this to calculate a read_size column which has the formula of

(read_bytes/read_ops = read_size). Note that read_ops could be 0 which

would yield a NULL in the read_size column. To avoid that, I use a

nested IF!

IF(SUM(IF(latx_stats_data.statname = 'read_ops', `statval`, 0)), 

(SUM(IF(latx_stats_data.statname = 'read_data', `statval`, 0)) /

SUM(IF(latx_stats_data.statname = 'read_ops', `statval`, 0))), 0) AS

'read_size'

I have to do this with several columns. I wonder if should read up on

stored procedures...

-- 

Scott <catfather AT donpoo.net>

AIM: BlueCame1

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Ilan Volow

"Implicit code is inherently evil, and here's the reason why:"