我试图使用LIMIT和OFFSET从数据库检索记录,效果很好,但是当我在末尾添加ORDER BY id时,它将失败.

我的代码是这样的：(这个很好用)

$sql6 = "SELECT * FROM products WHERE cat = 'category' LIMIT 10 OFFSET 0";
    $result6 = $conn->query($sql6);
        if ($result6->num_rows > 0) { 
        while($row6 = $result6->fetch_assoc()) { 
        echo $row6["position"];
} } else{}

在添加ORDER之后,它不会显示任何记录：

$sql6 = "SELECT * FROM products WHERE cat = 'category' LIMIT 10 OFFSET 0 ORDER BY id DESC";
    $result6 = $conn->query($sql6);
        if ($result6->num_rows > 0) { 
        while($row6 = $result6->fetch_assoc()) { 
        echo $row6["position"];
} } else{}

任何帮助表示赞赏.

解决方法:

LIMIT必须在语句的末尾：

SELECT * FROM products WHERE cat = 'category'  ORDER BY id DESC LIMIT 10 OFFSET  0

从documentation：

SELECT
[ALL | DISTINCT | DISTINCTROW ]
[HIGH_PRIORITY]
[STRAIGHT_JOIN]
[SQL_SMALL_RESULT] [SQL_BIG_RESULT] [SQL_BUFFER_RESULT]
[SQL_CACHE | SQL_NO_CACHE] [SQL_CALC_FOUND_ROWS]
select_expr [, select_expr …]
[FROM table_references
[WHERE where_condition]
[GROUP BY {col_name | expr | position}
[ASC | DESC], … [WITH ROLLUP]]
[HAVING where_condition]
[ORDER BY {col_name | expr | position}
[ASC | DESC], …]
[LIMIT {[offset,] row_count | row_count OFFSET offset}]
[PROCEDURE procedure_name(argument_list)]
[INTO OUTFILE ‘file_name’
[CHARACTER SET charset_name]
export_options
| INTO DUMPFILE ‘file_name’
| INTO var_name [, var_name]]
[FOR UPDATE | LOCK IN SHARE MODE]]

BTW：执行语句后检查错误