SQL 服务器中的 ALL IF Null 逻辑

Question

我们需要在网页中实现搜索功能。所以我们创建了一个存储过程来检索记录。逻辑是，当 i select 输入参数 Sp returns 参数的过滤记录时，它会检索所有可用记录。

例如：如果我给，

EXEC [WB_GetClassesByLocation_new2] null,null,null,'null',null,NULL,'N','N','N','N','N','N','N',NULL,null,null,null,null,null

（N 是天数字段的默认值） SP 将 return 所有可用的记录。如果我给，

EXEC [WB_GetClassesByLocation_new2] 1000,null,null,'null',null,NULL,'N','N','N','N','N','N','N',NULL,null,null,null,null,null。 SP 将 return 区 1000 的记录。我已经实现了以下逻辑

Select distinct c.classID, co.fCourseName as CourseName, StreetAddress + ', ' + l.City as LocationAddress, s.SessionName, sh.fShift as shift, StartTime, EndTime, c.classname, s.SessionID,
        c.StartDate,c.enddate 
        From dbo.vw_Class c 
        Inner Join dbo.lk_Session s 
        On (s.SessionID = c.sessionID) 
        Inner Join dbo.lk_Course co 
        On (co.CourseID = c.CourseID )
        Inner Join dbo.vw_Location l 
        On (l.locationid = c.locationid) 
        Inner Join lk_District d
        On (d.districtID = c.districtId) 
        Inner Join lk_Province p 
        On (p.provik = d.provik) 
        Inner Join lk_Shift sh 
        On (c.shiftid = sh.shiftid)
       where 
          c.DistrictID       =  case  when @Districtid is null   then c.DistrictID   else  @Districtid  end 
         and c.LocationID    =  case  when @locationid is null   then c.LocationID   else  @locationid  end 
         and s.SessionID     =  case  when @sessionid is null    then s.SessionID    else  @sessionid   end 
         and c.CourseID      =  case  when @levelid  is null     then c.CourseID     else  @levelid     end 
         and c.ShiftID       =  case  when @shiftid   is null    then c.ShiftID      else  @shiftid     end 
         and c.StartDate    >=  case  when @startdate is null    then c.StartDate    else  @startdate   end
         and c.EndDate      <=  case when  @enddate is null      then c.EndDate      else  @enddate     end
         and convert(time,c.StartTime) >= case when @starttime is null then convert(time,c.StartTime) else convert(time,@starttime) end
         and convert(time,c.endtime)   <= case when @endtime is null then convert(time,c.endtime) else convert(time,@endtime) end
         and c.Monday    = case  when @day1 = 'N' then c.monday     else  @day1  end 
         and c.Tuesday   = case  when @day2 = 'N' then c.Tuesday        else  @day2  end 
         and c.Wednesday = case  when @day3 = 'N' then c.Wednesday  else  @day3  end 
         and c.Thursday  = case  when @day4 = 'N' then c.Thursday       else  @day4  end 
         and c.Friday    = case  when @day5 = 'N' then c.Friday     else  @day5  end 
         and c.Saturday  = case  when @day6 = 'N'then c.Saturday        else  @day6  end 
         and c.Sunday    = case  when @day7 = 'N' then c.Sunday     else  @day7  end 
         and c.RowStatus    = 'A' 
         ORDER BY co.fCourseName, s.SessionID ,c.ClassName

但是 Sp 的执行时间太长了。这是在 sql 服务器中实现 "All IF null" 逻辑的正确方法吗？还有其他方法可以做到吗？

Answer 1

这是我的做法：

( @Districtid is null OR c.DistrictID = @Districtid )
AND
( @Locationid is null OR c.LocationID = @Locationid )
AND
...

但是，当您拥有非常多的此类过滤器，并且已经足够接近我要试验的临界点时，您最好创建一个动态 SQL 查询。

Answer 2

当你有很多过滤器的查询时，我知道 2 个选项：

使用 OR（如上建议），这会导致查询优化器扫描 table。请参阅此 post 了解更多信息：How to Optimize the Use of the "OR" Clause When Used with Parameters (SQL Server 2008)

使用动态 SQL - 这会导致查询优化器根据每个参数的每个变化计算执行计划一个好的选择是使用动态 sql 和 Bind Variables，这样优化器将缓存查询和执行计划。

declare @sql varchar(500)
DECLARE @ParmDefinition nvarchar(500);

SET @sql='select * from a where 1=1 '
 if @Locationid  is null
set @sql=@sql +' and @LocationId is null'
 else
 set @sql=@sql +' and LocationID= @LocationId'

  EXECUTE sp_executesql @sql, N'@LocationId int',
              @LocationID ;

SQL 服务器中的 ALL IF Null 逻辑

ALL IF Null logic in SQL Server

sql

tsql

sql-server

stored-procedures