Question

How to write a case in mysql query which checks for null or 0 for a particular column

CREATE TABLE tblConfirmationStatus (Confirm_Status TINY INT)

INSERT INTO tblConfirmationStatus 
Confirm_Status
VALUES
(1),
(0),
(1),
({null}),
(0),
(1),
({null})

Required Output

ConfirmStatus

   Confirmed
   Not Confirmed
   Confirmed
   Not Confirmed
   Not Confirmed
   Confirmed
   Not Confirmed

0 or Null – Not Confirmed, 1-Confirmed

SELECT CASE Confirm_Status 
            WHEN NULL OR 0 THEN 'Not Confirmed' 
             ELSE  'Confirmed' END AS ConfirmStatus
  FROM tblConfirmationStatus;

Answer 1

There’s two options for CASE statements – the one you posted, or:

SELECT CASE 
        WHEN Confirm_Status IS NULL OR Confirm_Status = 0 THEN 'Not Confirmed' 
        ELSE  'Confirmed' 
       END AS ConfirmStatus

But you could probably use:

SELECT CASE 
        WHEN Confirm_Status > 0 THEN 'Confirmed' 
        ELSE  'Not Confirmed' 
       END AS ConfirmStatus

NULL is the absence of a value, so checking for values above zero should fall into the same category as zero.