i am using MYSQL and i would like to "SELECT' a table and sort according to a numerical value that i either get it from "column1" or "column2", so:
if a number from column1 exist, then this number is used to be sorted, otherwise the number from column2 (which always exists) is the number used to be sorted
this is my current SQL statement:
WHERE regtime >=DATE_SUB(NOW(), INTERVAL 20 DAY)
ORDER BY regtime ASC
i think i should use "CASE" but what i can do now is only sort in "column1" first if column1 IS NOT NULL, THEN sort in "column2"
i appreciate your help as this is already one of my last stages on my personal website