How can I execute a comand if condition is true (SQL)

I want to compare 2 dates and if there´s a difference bigger than 2 days I want to update the field "data_fecho" from the table.

Here’s an example from the table

SELECT id,message,DATEDIFF(NOW(), lastupdate) AS dif FROM tickets;

Above I can get the difference between the dates but I can´t update it, doesn´t recognize dif

IF (dif > 2)
BEGIN
    UPDATE tickets set data_fecho=NOW()
END

>Solution :

You could add a where clause to your update statement:

UPDATE tickets
SET    data_fecho = NOW()
WHERE  DATEDIFF(NOW(), lastupdate) > 2