case 语句的问题?

zhuningqw

在第一个和第二个case 处发生错误            
select temp_num1.main_num mainnum,
        sum(case month(loanpact.ledate) when 1 then loanpact.balance else 0 end ) m1,
        sum(case month(loanpact.ledate) when 2 then loanpact.balance else 0 end ) m2,
        sum(case month(loanpact.ledate) when 3 then loanpact.balance else 0 end ) m3,
        sum(case month(loanpact.ledate) when 4 then loanpact.balance else 0 end ) m4,
        sum(case month(loanpact.ledate) when 5 then loanpact.balance else 0 end ) m5,
        sum(case month(loanpact.ledate) when 6 then loanpact.balance else 0 end ) m6,
        sum(case month(loanpact.ledate) when 7 then loanpact.balance else 0 end ) m7,
        sum(case month(loanpact.ledate) when 8 then loanpact.balance else 0 end ) m8,
        sum(case month(loanpact.ledate) when 9 then loanpact.balance else 0 end ) m9,
        sum(case month(loanpact.ledate) when 10 then loanpact.balance else 0 end ) m10,
        sum(case month(loanpact.ledate) when 11 then loanpact.balance else 0 end ) m11,
        sum(case month(loanpact.ledate) when 12 then loanpact.balance else 0 end ) m12
        from outer loanpact,temp_num1
        where loanpact.loankind_num = temp_num1.kindnum
        and year(loanpact.ledate) = year(today)
        group by 1