First use cursor and initially understand it

理解了数据库中的指针，但让凭空写出这些代码好像还有些困难，这可能是熟练的问题吧。

DECLARE @Customer VARCHAR(40),@Project VARCHAR(40)

DECLARE @NUM INT,@NUM1 INT,@iID INT

DECLARE CUR_Backlog CURSOR FOR

SELECT Customer,Project FROM BACKLOG

OPEN CUR_Backlog

FETCH NEXT FROM CUR_Backlog

INTO @Customer,@Project

WHILE @@FETCH_STATUS = 0

BEGIN

SELECT @NUM=COUNT(*) FROM PROJECT WHERE PROJECT=@Project AND CUSTOMER=@Customer

IF @NUM=0

BEGIN

SELECT @NUM1=COUNT(*) FROM FORECAST_12M WHERE PROJECT=@Project AND CUSTOMER=@Customer

INSERT INTO PROJECT VALUES(@Project,@Customer)

SET @iID=@@IDENTITY

IF @NUM1=0

INSERT INTO FORECAST_12M

VALUES(@iID,@Project,@Customer,0,0)

END

FETCH NEXT FROM CUR_Backlog

INTO @Customer,@Project

END

CLOSE CUR_Backlog

DEALLOCATE CUR_Backlog