i need a simple query which update mysql field with its value and some modification for example if field have value (3,4,5) i can add (,6) and this just in case it have value and if its NULL then update the field with the ","

i searched web and find mysql function called CONCAT and it Returns the string that results from concatenating the arguments.

i tried this one but this didn't work

UPDATE groups SET SubsID = CONCAT(SubsID,",5") WHERE GroupID = 2

it return no issue but 0 rows affected and field not updated

解决方案UPDATE GROUPS

SET SubsID = CASE WHEN SubsID IS NULL THEN '6'

ELSE CONCAT(SubsID, ',6')

END

WHERE GroupID = 2