我有一个表的更新语句公式,并且该语句有效,但我想每次添加新数据时自动更新我的表,所以我认为我应该使用View。
这是我的更新声明:
followers f left outer join
followers f2
on f2.id = f.id
set f.Growth = f.Growth_Speed/(SELECT AVG(f.Growth_Speed) FROM (SELECT f.Growth_Speed from followers f WHERE f.id <= f.id+1));
这是我的View声明:
CREATE VIEW `followers_view` AS
select
`followers`.`id` AS `id`,
`followers`.`date` AS `date`,
`followers`.Growth_Speed` AS `Growth_Speed`
From `my_database.followers`;
我想将该更新语句添加为View中的第四列,但不确定如何执行此操作。
由于
答案 0 :(得分:0)
您必须在插入新数据时将Trigger设置为要进行更新的表
代码将是这样的:
CREATE TRIGGER update_table AFTER INSERT ON followers
FOR EACH ROW
BEGIN
followers f left outer join followers f2 on f2.id = f.id
set f.Growth = f.Growth_Speed/(SELECT AVG(f.Growth_Speed) FROM (SELECTf.Growth_Speed from followers f WHERE f.id <= f.id+1));
END
我猜是关注者是您插入数据的表,以及您要更新的数据。