mysql - MySQL SELECT 使用基于来自另一个字段的数据的字符串

Question

这有效：

SELECT `nid`, CONCAT('node/', `nid`) AS `vpath`, `title`
FROM `node` WHERE MATCH(`title`) AGAINST ('a*' IN BOOLEAN MODE)

那么为什么这不起作用：

SELECT `nid`, CONCAT('node/', `nid`) AS `vpath`, `title`, `alias`
FROM `node` WHERE MATCH(`title`) AGAINST ('a*' IN BOOLEAN MODE)
LEFT JOIN `url_alias` ON `url_alias`.`source` = `vpath`

Answer 1

JOIN 应该放在 WHERE 语句之前。尝试：

SELECT `nid`, CONCAT('node/', `nid`) AS `vpath`, `title`, `alias`
FROM `node`
LEFT JOIN `url_alias` ON `url_alias`.`source` = `vpath`
WHERE MATCH(`title`) AGAINST ('a*' IN BOOLEAN MODE)

MYSQL 选择语法