Question

I am currently using two update queries and am wondering if there is a way to cut it down to one.

field1 OFTYPE INT
field2 OFTYPE DATETIME
field3 OFTYPE DATETIME

UPDATE `Table1` SET `field1` = `field1` + 1, `field2` = NOW() WHERE `id` = $id;
UPDATE `Table1` SET `field3` = NOW() WHERE `id` = $id AND (`field3` < '2011-00-00 00:00:00' OR `field3` IS NULL);

I’m trying to get a query that would do the UPDATE more like so:

UPDATE `Table1` 
SET `field1` = `field1` + 1,
    `field2` = NOW(),
    `field3` = ISNULL(NOW(), `first_seen`);

Answer 1

I think that’s it’s possible for you to do this using an IF statement. The IF statement takes 3 parameters when you’re using it: the expression, value if true, value if false

So in your case, you could probably write your queries in one go like the following:

UPDATE Table1 
SET 
    field1 = field1 + 1, 
    field2 = NOW(),
    field3 = IF(field3 < '2011-00-00 00:00:00' OR field3 IS NULL, NOW(), field3)
WHERE id = $id;

This way, if expression is true, then field3 will be NOW() and otherwise, it’ll remain as it was.