PHP SQL Conditional queries?

[ole90]

I'm trying to do a query like this:

$u=mysql_query("UPDATE `Member` IF `prem_days` > '0' THEN `prem_days` = `prem_days` - 1 ELSE `premium` = 'no' AND `prem_days` = '0'") or die(mysql_error()); 

But this doesn't seem to work. The other alternative is to use two queries but I'd rather not as my DB is very query intensive as it is already :P

Any help with this would be greatly appriciated ^_^

[longneck]

before running a query that modifies data, make sure you have a backup and that you know how to restore it properly!

one of these two will work. i don't have time to test if for you right now, so i suggest using a transaction to verify which one is correct.

UPDATE Member
   SET prem_days = GREATEST(0, prem_days - 1)
     , premium = CASE prem_days WHEN 0 THEN 'no' ELSE premium END

UPDATE Member
   SET prem_days = GREATEST(0, prem_days - 1)
     , premium = CASE prem_days - 1 WHEN 0 THEN 'no' ELSE premium END

[ole90]

Thanks