MySQL视图表创建与修改

1、创建 CREATE [OR REPLACE] [lt;algorithm attributesgt;] VIEW [database.]lt; namegt; [(lt;columnsgt;)]AS lt;selec

1、创建

CREATE [OR REPLACE] [] VIEW [database.] [()]
AS []
例子：

CREATE VIEW `view_articles`
AS
SELECT
a.id AS id,
a.title AS title,
a.content AS content,
t.name AS tagname,
u.firstname AS "username"
FROM `articles` a
LEFT JOIN `tags` t
ON a.tag_id = t.id
LEFT JOIN `users` u
ON a.user_id = u.id
ORDER BY a.posttime DESC;
修改

ALTER [] VIEW [.] [()]
AS []
例子：

ALTER VIEW `view_articles`
AS
SELECT
a.id AS id,
a.title AS title,
a.content AS content,
a.posttime AS posttime,
t.name AS tagname,
CONCAT(u.firstname,' ',u.lastname) AS "username"
FROM `articles` a
LEFT JOIN `tags` t
ON a.tag_id = t.id
LEFT JOIN `users` u
ON a.user_id = u.id
ORDER BY a.posttime DESC;

修改已经建立好的视图表，最简单的方法就是在phpMyAdmin导出视图表的SQL，然后修改开头的“CREATE”（后面的”ALGORITHM=UNDEFINED DEFINER=`root`@`localhost` SQL SECURITY DEFINER”等不用管，保留它）为”ALTER”，运行语句即可。

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