SQL中，如何在表A中插入或者更新一条数据的同时能将该数据更新到表B中去

create trigger TR_A_IU on A for INSERT, update as BEGIN DECLARE @kmlx NUMERIC(10), @xxrs NUMERIC(10) SELECT @kmlx = 科目类型 FROM inserted SELECT @xxrs = isnull(sum(选修人数), 0) FROM A WHERE 科目类型 = @kmlx IF (SELECT count(1) FROM B WHERE 科目类型 = @kmlx