Question

我对简单查询有点问题。这是：

SELECT `T_COURS`.`COU_DATE`,
`T_SESSIONS`.*,
`T_FORMATIONS`.`FOR_TITRE`, `T_FORMATIONS`.`FOR_ID`, `T_FORMATIONS`.`FOR_TITRE`,     `T_FORMATIONS`.`FOR_CATEGORIE`,
`T_FORMATIONS`.`FOR_DESCRIPTION`, `T_FORMATIONS`.`FOR_MIN_PART`, `T_FORMATIONS`.`FOR_MAX_PART`, `T_FORMATIONS`.`FOR_PRIX`, `T_FORMATIONS`.`FOR_LANGUE`
FROM `T_FORMATIONS`
INNER JOIN `T_COURS` ON `T_SESSIONS`.`SES_ID` = `T_COURS`.`COU_SES_ID`
INNER JOIN `T_SESSIONS` ON `T_FORMATIONS`.`FOR_ID` = `T_SESSIONS`.`SES_FOR_ID`
WHERE `T_SESSIONS`.`SES_ETAT` = 1
ORDER BY `T_COURS`.`COU_DATE` ASC, `T_SESSIONS`.`SES_TITRE` ASC, `T_FORMATIONS`.`FOR_TITRE` ASC LIMIT 5

当我尝试运行它时，我收到此消息：

#1054 - Unknown column 'T_SESSIONS.SES_ID' in 'on clause'

我真的不明白为什么因为我的数据库中存在所有内容？

我在互联网上寻找答案，但它对我没有帮助（或者我没有理解我读到的答案）。

Answer 1

如果没有看到您的完整表格结构，我会首先交换您的JOIN订单，在您尝试在当前版本中使用它之后加入T_SESSIONS。你现在有：

FROM `T_FORMATIONS`
INNER JOIN `T_COURS` 
  ON `T_SESSIONS`.`SES_ID` = `T_COURS`.`COU_SES_ID`
INNER JOIN `T_SESSIONS` 
  ON `T_FORMATIONS`.`FOR_ID` = `T_SESSIONS`.`SES_FOR_ID`

将其更改为：

FROM `T_FORMATIONS`
INNER JOIN `T_SESSIONS` 
  ON `T_FORMATIONS`.`FOR_ID` = `T_SESSIONS`.`SES_FOR_ID`
INNER JOIN `T_COURS` 
  ON `T_SESSIONS`.`SES_ID` = `T_COURS`.`COU_SES_ID`

完整查询：

SELECT `T_COURS`.`COU_DATE`,
  `T_SESSIONS`.*,
  `T_FORMATIONS`.`FOR_TITRE`, 
  `T_FORMATIONS`.`FOR_ID`, 
  `T_FORMATIONS`.`FOR_TITRE`,     
  `T_FORMATIONS`.`FOR_CATEGORIE`,
  `T_FORMATIONS`.`FOR_DESCRIPTION`, 
  `T_FORMATIONS`.`FOR_MIN_PART`, 
  `T_FORMATIONS`.`FOR_MAX_PART`, 
  `T_FORMATIONS`.`FOR_PRIX`, 
  `T_FORMATIONS`.`FOR_LANGUE`
FROM `T_FORMATIONS`
INNER JOIN `T_SESSIONS` 
  ON `T_FORMATIONS`.`FOR_ID` = `T_SESSIONS`.`SES_FOR_ID`
INNER JOIN `T_COURS` 
  ON `T_SESSIONS`.`SES_ID` = `T_COURS`.`COU_SES_ID`
WHERE `T_SESSIONS`.`SES_ETAT` = 1
ORDER BY `T_COURS`.`COU_DATE` ASC, `T_SESSIONS`.`SES_TITRE` ASC, `T_FORMATIONS`.`FOR_TITRE` ASC 
LIMIT 5

Mysql - ON子句中的未知列

1 个答案: