Error 1241 Operand should contain 2 column(s)

Question

My query : http://pastebin.com/8c2rLrRk

In this 3rd case 2nd when condition is causing the issue, if i comment that then query is running well. So pls let me know where the loophole in this syntax.

Answer 1

Error line: IFNULL(COUNT(blockedseats.seatNo),0) We can't club count and ifnull functions.