SQL LEN() 函数 ,case when,聚合函数的使用方法

SELECT aa.[User_Id],cc.[User_Name],dd.Name AS DepName,aa.Module_Id,aa.Module_Name,

SUM(CASE aa.Operate_Type WHEN '2' THEN OperateNum END ) AS 'AddNum', 

SUM(CASE aa.Operate_Type WHEN '3' THEN OperateNum END ) AS 'EditNum' , 

SUM(CASE aa.Operate_Type WHEN '4' THEN OperateNum END ) AS 'DelNum' 

FROM (

SELECT a.[User_Id],a.Module_Id,c.Module_Name,a.Operate_Type,COUNT(1) AS OperateNum FROM dbo.Sys_User_Log AS a 

INNER JOIN dbo.Sys_Module AS c ON a.Module_Id = c.Module_Id

WHERE LEN(a.Module_Id) = 6 AND (a.Operate_Type ='2' OR a.Operate_Type ='3' OR a.Operate_Type ='4')//LEN() 函数

GROUP BY a.[User_Id],a.Module_Id,c.Module_Name,a.Operate_Type

) AS aa

INNER JOIN dbo.Sys_User AS cc ON aa.[User_Id] = cc.[User_Id]

INNER JOIN dbo.Sys_DepInfo AS dd ON cc.DepInfo_Id = dd.Id

GROUP BY aa.[User_Id],cc.[User_Name],dd.Name,aa.Module_Id,aa.Module_Name

ORDER BY aa.[User_Id],aa.Module_Id