i cant declaring in query

Question

@a =( CASE WHEN amount IS NOT NULL THEN amount1 
      WHEN percentage IS NOT NULL THEN sco.amount *  1 + (percentage / 100) END) AS data1

without @a i am getting result but with @a i am not getting result

Answer 1

Try like this below , you were missing :

@a :=( CASE WHEN amount IS NOT NULL THEN amount1 
          WHEN percentage IS NOT NULL THEN sco.amount *  1 + (percentage / 100) END) AS data1