mysql - 如何从我的 sql 表中选择最后 5 条记录

Question

我正在从服务器获取数据。我希望该用户只能获得表中的最后 5 条记录。

这是我目前正在使用的查询；它不工作：

 $query = mysql_query("
          SELECT 
          ml.PostID, 
          ml.UserID, 
          ml.PostDate, 
          ml.PostTime, 
          ml.PostCategory, 
          ml.PostSubCategory, 
          ml.PostComments, 
          cat.UserName
          FROM UserPosts AS ml
          LEFT JOIN UserNames cat 
          ON cat.UserID = ml.UserID 
          ORDERD BY DESC LIMIT 5");

给出以下错误

警告：mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in /home/content/i/h/u/ihus235/html/cs/pah_brd_v1/productivo/getPosts.php on line 77

Answer 1

按子句顺序添加列名

SELECT ml.PostID, 
       ml.UserID, 
       ml.PostDate, 
       ml.PostTime, 
       ml.PostCategory, 
       ml.PostSubCategory, 
       ml.PostComments, 
       cat.UserName
FROM UserPosts AS ml
LEFT JOIN UserNames cat 
ON cat.UserID = ml.UserID 
ORDER BY ml.PostComments DESC 
LIMIT 5

Answer 2

$sql = 'SELECT ml.PostID, 
       ml.UserID, 
       ml.PostDate, 
       ml.PostTime, 
       ml.PostCategory, 
       ml.PostSubCategory, 
       ml.PostComments, 
       cat.UserName
FROM UserPosts AS ml
LEFT JOIN UserNames cat 
      ON cat.UserID = ml.UserID 
ORDER BY ml.PostTime DESC LIMIT 5';

$query = mysql_query($sql) or die(mysql_error());

尝试这个。