sql server求和问题

Question

求解，sql server如何实现用上一行的余额+借方金额-贷方余额自动填充余额？能否使用触发器实现？上代码

Answer 1

可以的，和正常的写法差不多，只是记得取上一条记录的时候用额外表的一行加个写锁，或者把这个表的第一行加写锁

-- Description:    <Description,,>
-- =============================================
ALTER TRIGGER [dbo].[yuetb_trigger] 
   ON  [dbo].[yuetb]
   AFTER INSERT
AS 
BEGIN

    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for trigger here

    DECLARE TEMP_IGNOR CURSOR FOR select top 1 * from dbo.yuetb order by 序列 for update;
    declare @序列 int;
    SELECT @序列=序列 FROM inserted;
    update dbo.yuetb set 余额=(select top 1 余额 from dbo.yuetb where 序列< @序列 order by 序列 DESC )+isnull(借方,0)-isnull(贷方,0) where 序列=@序列;
END
DEALLOCATE TEMP_IGNOR;