SQL語法查詢錯誤

-4

SELECT 
    'posts'.'post_id' AS 'id', 
    'posts'.'post_title' AS 'title', 
    LEFT('posts','post_body', 512) AS 'preview', 
    'posts'.'post_user' AS 'user', 
    DATE_FORMAT('posts'.'post_date', '%d/%m/%Y %H:%i:%s') AS 'DATE', 
    'comments'.'total_comments', 
    DATE_FORMAT('comments'.'last_comment', '%d/%m/%Y %H:%i:%s') AS 'last_comment' 
    FROM 'posts' 
    LEFT JOIN (
     SELECT 
     'post_id', 
     COUNT('comment_id') AS 'total_comments', 
     MAX('comment_date') AS 'last_comment' 
     FROM 'comments' 
     GROUP BY 'post_id' 
    ) AS 'comments' 
    ON 'posts'.'post_id' = 'comments'.'post_id' 
    ORDER BY 'posts'.'post_date' DESC

的問題，我得到：

＃1064 - 你在你的SQL語法錯誤;檢查與您的MySQL服務器版本相對應的手冊，以便在'。'post_id'AS'id'，'posts'，'post_title'AS'標題'，LEFT（'posts'，'p'at line 2

來源

2013-06-12 ddacot

既然你正在使用MySQL使用反引號而不是單引號圍繞表，列和別名。 – Taryn

這是一個所謂的PICNIC錯誤。 –

不要使用正常的撇號（「'」），但在MYSQL中反引號「`」。正常的撇號用於引用字符串。還請注意，我更改了逗號

LEFT(`posts`,`post_body`, 512) as `preview`

到一段時間。

它應該閱讀：

SELECT 
     `posts`.`post_id` AS `id`, 
     `posts`.`post_title` AS `title`, 
     LEFT(`posts`.`post_body`, 512) AS `preview`, 
     `posts`.`post_user` AS `user`, 
     DATE_FORMAT(`posts`.`post_date`, '%d/%m/%Y %H:%i:%s') AS `DATE`, 
     `comments`.`total_comments`, 
     DATE_FORMAT(`comments`.`last_comment`, '%d/%m/%Y %H:%i:%s') AS `last_comment` 
     FROM `posts` 
     LEFT JOIN (
      SELECT 
       `post_id`, 
       COUNT(`comment_id`) AS `total_comments`, 
       MAX(`comment_date`) AS `last_comment` 
       FROM `comments` 
       GROUP BY `post_id` 
       ) AS `comments` 
     ON `posts`.`post_id` = `comments`.`post_id` 
     ORDER BY `posts`.`post_date` DESC

來源

2013-06-12 14:20:04

謝謝，但我得到了＃1054 - '字段列表'中的未知列'posts.post_id' – ddacot

那麼，表中是否有'post_id'列？ –

您使用字符串文字作爲表：

FROM 'posts'

如果您想逃跑的表名，使用反引號，如：

FROM `posts`

逸出表名不是必需的; from posts是完全正常的。

來源

2013-06-12 14:19:28 Andomar

我認爲，你的左邊的語法錯誤時，第一個逗號改爲一段

LEFT('posts','post_body', 512) AS 'preview',

應該

LEFT('posts'.'post_body', 512) AS 'preview',

來源

2013-06-12 14:20:36 Sparky

SQL語法查詢錯誤

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