自己写的一个 游标 实例

1游标实现
三张 关联的表 的游标操作
at  字段 AID ANAME
bt  字段 BID BNAME AID
ct  字段 CID CNAME  BID
通过循环读取at中的id 更新bt中的name 再根据bt中id循环更新ct中的name

--SET NOCOUNT ON 显示受影响的行数
DECLARE @AID INT
DECLARE @BID INT

DECLARE publish_cursor CURSOR FOR
SELECT Aid FROM aT
    OPEN publish_cursor
    FETCH NEXT FROM publish_cursor
    INTO @AID

        WHILE @@FETCH_STATUS = 0
        BEGIN
        print @AID
            --修改记录
                update BT set BNAME=GETDATE() where Aid=@Aid

     DECLARE publish_cursor2 CURSOR FOR
     SELECT Bid FROM BT
     OPEN publish_cursor2

    FETCH NEXT FROM publish_cursor2
    INTO @BID
    print @BID
     update CT set CNAME=GETDATE() where Bid=@Bid
      --修改结束
     FETCH NEXT FROM publish_cursor2 into @Bid

                  CLOSE publish_cursor2
                  DEALLOCATE    publish_cursor2

            --修改结束
            FETCH NEXT FROM publish_cursor into @Aid
           
        END
    CLOSE publish_cursor
    DEALLOCATE publish_cursor
   
GO

2用CTE实现 WITH(但是他只能对紧接着的sql语句有效，所以只能执行一部操作)
       ;WITH atInfo as (SELECT * FROM aT where aid=1),
       btInfo as (SELECT * FROM bT where bid in (select AID from atInfo))
--       Update BT set bName = 'WITH'  WHERE AID in (select AID from atInfo)
       Update cT set cName = 'WITHc'  WHERE bID in (select bID from btInfo);
  select * from ct;