简单但有用的SQL脚本Part：游标模板

时间：2010-09-08 来源：听风吹雨

游标是很常使用的SQL，所以这里给出一个模板，这里需要注意变量的命名和书写格式。

--模板
DECLARE @ID int, @GUID varchar(50),@LoginName varchar(50)
DECLARE @itemCur CURSOR
SET @itemCur = CURSOR FOR
    SELECT ID,GUID,LoginName FROM [TableName]
    WHERE LoginName =  ''

OPEN @itemCur
FETCH NEXT FROM @itemCur INTO @ID,@GUID,@LoginName
WHILE @@FETCH_STATUS=0
BEGIN
    --逻辑处理

    FETCH NEXT FROM @itemCur INTO @ID,@GUID,@LoginName
END

CLOSE @itemCur
DEALLOCATE @itemCur

下面是一个游标的使用模板，里面的逻辑处理形如：PosSet：[573,1103,2010-09-03 22:32:35],[864,110,2010-09-03 22:32:57]这样字符串的分割，这个字段表示用户点击页面的坐标和时间。注意当字符串是PosSet：[573,1103,2010-09-03 22:32:35]时候的情况，因为这个时候就没有分隔字符在字符串了。关于这个问题的详细记录见：简单但有用的SQL脚本Part

--实例
DECLARE @ID int, @GUID varchar(50),@LoginName varchar(50),@PosSet varchar(2000), @Resolution varchar(20)
DECLARE @splitlen int
DECLARE @split nvarchar(10)
DECLARE @Temp varchar(100)
DECLARE @PosSet_x int
DECLARE @PosSet_y int
--set @split = '],'
set @split = ']'
DECLARE @itemCur CURSOR
SET @itemCur = CURSOR FOR
    SELECT ID,GUID,LoginName,PosSet,Resolution FROM [VisiteLog_Statistical_Temp]
    WHERE PosSet <> ''

OPEN @itemCur
FETCH NEXT FROM @itemCur INTO @ID,@GUID,@LoginName,@PosSet,@Resolution
WHILE @@FETCH_STATUS=0
BEGIN
    SET @splitlen=LEN(@split+'a')-2
    WHILE CHARINDEX(@split,@PosSet)>0
    BEGIN
        SET @Temp = LEFT(@PosSet,CHARINDEX(@split,@PosSet)-1)
        SET @Temp = replace(@Temp,'[','')
        SET @PosSet_x = dbo.Get_StrArrayStrOfIndex(@Temp,',',1)
        SET @PosSet_y = dbo.Get_StrArrayStrOfIndex(@Temp,',',2)
        INSERT t_Guid VALUES(@ID,@GUID,@LoginName,@Resolution,@PosSet_x,@PosSet_y)
        SET @PosSet=STUFF(@PosSet,1,CHARINDEX(@split,@PosSet)+@splitlen,'')
    END
    IF NOT EXISTS(SELECT ID FROM t_Guid WHERE ID = @ID)--只有一个坐标
    BEGIN
        SET @Temp = replace(replace(@PosSet,'[',''),']','')
        SET @PosSet_x = dbo.Get_StrArrayStrOfIndex(@Temp,',',1)
        SET @PosSet_y = dbo.Get_StrArrayStrOfIndex(@Temp,',',2)
        INSERT t_Guid VALUES(@ID,@GUID,@LoginName,@Resolution,@PosSet_x,@PosSet_y)
        --print @GUID
    END

    FETCH NEXT FROM @itemCur INTO @ID,@GUID,@LoginName,@PosSet,@Resolution
END

CLOSE @itemCur
DEALLOCATE @itemCur