SQL返回0行的结果

Question

    function getData()
    {
        $select_query = "SELECT Value FROM Allies WHERE 'Key'='14638'";

        mysqli_real_escape_string($this -> dataConnection, $this -> cacheKey);
        mysqli_real_escape_string($this -> dataConnection, $this -> id);

        if ($result = $this -> dataConnection ->query($select_query)) {
            printf("Select returned %d rows.\n", $result->num_rows);

            /* free result set */
            $result->close();
        }

    }

出于某种原因,此代码在数据存在时打印"选择返回的0行",而在数据不存在时打印任何内容.

这是数据的屏幕截图,如果有帮助:

我该如何修复它并访问数据？

Answer 1

Key是一个保留字.所以使用bacticks而不是引号:

改变这个:

 $select_query = "SELECT Value FROM Allies WHERE 'Key'='14638'";

至:

 $select_query = "SELECT Value FROM Allies WHERE `Key`='14638'";