Update a columns if certain value

Question

I have a certain column in a table that stores a number. I want this number to be set to 2 ONLY if it previously equaled 1. I was wondering if it was possible to avoid this:

$val = mysql_fetch_row(mysql_query("SELECT columnA FROM tableName WHERE something = '$someValue'"));

if($val[0] == 1) { .....UPDATE tableName SET columnA = 2....... }

Is it possible to directly query the database? With something like this:

SET columnA = 2 if columnA = 1

There is really no need to bring PHP logic into this, just do it all in one MySQL UPDATE statement as seen below — Barry Chapman
– Barry Chapman, Commented Feb 8, 2012 at 6:58

Mosty Mostacho · Accepted Answer · 2012-02-08 06:56:33Z

12

Actually the query you're looking for should be:

update tableName set columnA = 2
where columnA = 1

The "if" you're mentioning is actually a condition. And these conditions are set in the where clause of the update statement.

That's it :)

answered Feb 8, 2012 at 6:56

Mosty Mostacho

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Rudiger · Accepted Answer · 2012-02-08 06:57:24Z

3

UPDATE tableName SET columnA = 2 WHERE columnA = 1

answered Feb 8, 2012 at 6:57

Rudiger

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Michał Powaga · Accepted Answer · 2012-02-08 06:59:23Z

3

Why not just do an update with conditions?

UPDATE tableName SET columnA = '2' WHERE columnA = '1'

That should do what you are looking for

edited Feb 8, 2012 at 6:59

Michał Powaga

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answered Feb 8, 2012 at 6:57

Barry Chapman

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