Question

尝试学习触发器，似乎无法为这是否是实现此目标的最佳方法而wrap之以鼻。我想算一共“票”，并将其放入“订单”列中。

CREATE TRIGGER DAILYTICKETTOTALS    
ON db.ORDER 
AFTER UPDATE
AS 
BEGIN
INSERT INTO db.ORDER (
    --Finding the order they made for the day:
    SELECT * FROM db.ORDER
    WHERE DESCRIPTION = 'specific description' AND 
          CAST(CAST(CAST(GETDATE()AS float) AS int) AS datetime) =  
          CAST(CAST(CAST(db.ORDER.STARTDATE AS float) AS int) AS datetime)
          AND db.ORDER.CREATEDBY = 'Last, First'
)
SET db.ORDER.COLUMNTOTALS VALUES(  
    --Finding the total of tickets input for the day
    SELECT COUNT(*)
    FROM db.ticket 
    WHERE CAST(CAST(CAST(db.ticket.DATE AS float) AS int) AS datetime) = 
          CAST(CAST(CAST(GETDATE()AS float) AS int) AS datetime)
          AND db.ticket.INPUTBY = 'Last, First');

感谢您的帮助，感谢您对此进行审查。

Answer 1

对触发器中可用的“特殊”表进行一些研究，例如“ INSERTED”，因为这将为您提供已更新行的详细信息，并且您可以将其与其他任何内容（包括实际表）联系起来正在更新）。请记住，您不应该假设仅更新了1行，因为触发器将每批触发一次，而不是每行触发一次。

这是存储过程的一个版本，该版本假定每个订单都有一个名为OrderID的唯一ID，并且票证和订单表都具有personID，而不是按名称查找它们。如果没有，他们应该这样做，如果您不能更改它，则使用现有的混乱连接。

CREATE TRIGGER DAILYTICKETTOTALS    
ON db.ORDER 
AFTER UPDATE
AS 
BEGIN
    update o
    set columntotals=TicketNum
    from inserted
    join db.[order] o on o.orderid=inserted.orderid
    join (
        select convert(date,ticket,[date]) as ticketdate, PersonID, count(*) as TicketNum
        from db.ticket
        group by convert(date,ticket,[date]) as ticketdate, PersonID
        ) t on t.PersonID=o.PersonID and t.ticketdate=convert(date,getdate())

Answer 2

这可以解决我的问题，以防万一您好奇。我不知道它是否理想，但是可以。

CREATE TRIGGER DAILYTICKETTOTALS    
ON db.ORDER 

AFTER INSERT, UPDATE
AS 
BEGIN
DECLARE @INS NVARCHAR(50)
SELECT @INS = NAMECOLUMN FROM INSERTED
WHERE DESCRIPTION = 'specific description' AND 
CAST(CAST(CAST(STARTDATE AS float) AS int) AS datetime)=
CAST(CAST(CAST(GETDATE() AS float) AS int) AS datetime)
END
IF @INS = ‘Last, First’

BEGIN

UPDATE db.ORDER
SET COLUMNTOTALS  =  EXAMPLENAME.CT

FROM (SELECT COUNT(*) AS CT FROM ticket WHERE INPUTBY = ‘Last, First’) EXAMPLENAME
WHERE DESCRIPTION = 'specific description' AND INPUTBY = ‘Last, First’ 
END
BEGIN

SQL Server触发器。用另一个表中的列数更新一个表中的列

2 个答案: