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。我希望该用户只能得到表格中的最后5条记录。

这是我目前使用的查询;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

$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()); 

尝试这种添加列名。

Answer 2

在ORDER BY子句

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