求将SQL语句的IIf(Mid改用case when...else...end

忘得快

请教将以下语句的红色部分：
strSql = "SELECT XB.B AS 财务分类, A.收费金额, A.收费项目" _
    & "FROM (SELECT Left([财务分类],IIf(Mid([财务分类],2,1)="",1,2)) AS A, Mid([财务分类],3,20) AS B " _
    & "FROM B) AS XB INNER JOIN A ON XB.A = A.收费项目;"

改为用:case when...else...end
谢谢！

roych

case substring([财务分类],2,1)
when "'"
then substring([财务分类],1,1)
eslse
substring([财务分类],1,2)
end