SQL 优化实战

1 　　DECLARE @UserCount1 INT    --VIP等级大于28的用户数
2     SELECT T.UserID INTO #TempTableOf28
3     FROM GAMECENTERLINKEDSERVER.GameCenter.LevelSystem.VIP_UserGrade  VG ,#TempTable T
4     WHERE VG.UserID = t.UserID  AND VG.Grade>=28  ORDER BY VG.Grade DESC           --倒叙，高VIP等级优先获奖
5     SELECT @UserCount1=COUNT(UserID) FROM #TempTableOf28

1  　　DECLARE @StringUserID1 VARCHAR (max) 
2 　　 SET @StringUserID1=‘‘  
3     IF EXISTS(SELECT  1 FROM  #TempTableOf28 ) AND @UserCount1<=1000  --VIP等级大于28，要么不足1000，要么直接取完，取完改@DrawCount=0，不再执行其他部分
4     　　SELECT  @StringUserID1=@StringUserID1+‘,‘+CAST(UserID AS VARCHAR) FROM #TempTableOf28
5     ELSE IF EXISTS(SELECT 1 FROM  #TempTableOf28 ) AND @UserCount1>1000
6     　　SELECT TOP 1000  @StringUserID1=@StringUserID1+‘,‘+CAST(UserID AS VARCHAR) FROM #TempTableOf28

 1 IF (SELECT COUNT(1) FROM @vip)<=1000
 2     INSERT INTO @UsersLast
 3     SELECT UserID FROM @vip
 4 ELSE IF (SELECT COUNT(1) FROM @vip WHERE Vip>=28)>=1000
 5     INSERT INTO @UsersLast
 6     SELECT TOP 1000 UserID FROM @vip WHERE vip>=28
15 ELSE
16     INSERT INTO @UsersLast
17     SELECT TOP 1000 UserID FROM @vip
18     ORDER BY vip DESC