Mysql - ON子句中的未知列

Question

我遇到了一個簡單查詢的問題。那就是：

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 

當我嘗試運行它，我得到這個消息：

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

我真的不明白爲什麼，因爲一切都在我的數據庫中是否存在？

我在網上尋找答案，但它沒有幫助我（或者我不明白我讀的答案）。

Answer 1

沒有看到您的全表結構，我會開始交換您的訂單JOIN，您在嘗試在當前版本中使用它時加入T_SESSIONS。您目前有：

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` 

將其更改爲：

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` 

製作完整的查詢：

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