需求：在河道水情表（ST_RIVER_R ）新增插入資料時，更新實時資料表（SS_data） 中關聯欄位的值。

需求概括下：當A表中新增資料時，同時更新B表中的某欄位

程式碼如下：

USE [DBCNBZ]
GO

/****** Object:  Trigger [dbo].[tri_insert_a]    Script Date: 2021/11/10 14:17:00 ******/
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

-- =============================================
-- Author:        <Author,,Name>
-- Create date: <Create Date,,>
-- Description:    <Description,,>
-- =============================================
CREATE trigger [dbo].[tri_insert_a]
on [dbo].[ST_RIVER_R] 
after insert
 
as
begin

declare @Z1 numeric(18,3);
declare @Q1 numeric(18,3);
declare @Z2 numeric(18,3);
declare @Q2 numeric(18,3);
declare @Z3 numeric(18,3);
declare @Q3 numeric(18,3);
declare @TM1 datetime;
declare @TM2 datetime;
declare @TM3 datetime;

--一站
select top 1 @Z1 = Z from [ST_RIVER_R] where STCD='00000001'
 
 order by TM desc;
select top 1 @Q1 = Q from [ST_RIVER_R] where STCD='00000001' order by TM desc;
select top 1 @TM1 = TM from [ST_RIVER_R] where STCD='00000001' order by TM desc;

--二站
select top 1 @Z2 = Z from [ST_RIVER_R] where STCD='00000002' order by TM desc;
select top 1 @Q2 = Q from [ST_RIVER_R] where STCD='00000002' order by TM desc;
 
select top 1 @TM2 = TM from [ST_RIVER_R] where STCD='00000002' order by TM desc;

--三站
select top 1 @Z3 = Z from [ST_RIVER_R] where STCD='00000013' order by TM desc;
select top 1 @Q3 = Q from [ST_RIVER_R] where STCD='00000013' order by TM desc;
select top 1 @TM3 = TM from [ST_RIVER_R] where STCD='00000013' order by TM desc;

begin
update [dbo].[SS_data] set water1=@Z1,[SunShiFlow1]=@Q1,TM=@TM1

where [dbo].[SS_data].Num ='Z1';

update [dbo].[SS_data] set water1=@Z2,[SunShiFlow1]=@Q2,TM=@TM2

where [dbo].[SS_data].Num ='Z2';

update [dbo].[SS_data] set water1=@Z3,[SunShiFlow1]=@Q3,TM=@TM3

where [dbo].[SS_data].Num ='Z3';
end
 
end


GO

我這裡是每次更新了SS_data中三個欄位的值，SS_data是一張實時資料表，每次都是update操作，每個測站保留最新的一條資料。

這裡注意下 觸發器的變數定義和賦值的方式

declare @TM3 datetime;

--一站
select top 1 @TM3 = TM from [ST_RIVER_R] where STCD='00000001' order by TM desc;