Question

以下是我的疑问：

$sql = "SELECT date, status, reason 
        FROM tbl_attendance_mgmt ORDER BY date $order 
        LIMIT $number 
        WHERE fk_stu_id = '$stu_id'";

下面：

$order: ASC or DESC
$number: Number of rows to be displayed.

有人可以帮我解释为什么这个查询在执行时会给我错误吗？

Answer 1

您必须遵循sql查询的顺序。在{by} by order by

之前WHERE

$sql = "select `date`, status, reason from tbl_attendance_mgmt  where fk_stu_id = '$stu_id' order by `date` $order limit $number";

Answer 2

以这种方式编写查询：

$sql = "SELECT date, status, reason 
        FROM tbl_attendance_mgmt
        WHERE fk_stu_id = '{$stu_id}' 
        ORDER BY date $order 
        LIMIT $number ";

你必须使用花括号{}

绑定你的php变量

Answer 3

$sql = "SELECT date, status, reason 
FROM tbl_attendance_mgmt
WHERE fk_stu_id = " . mysqli_real_escape_string($con, $stu_id) . "
ORDER BY date $order 
LIMIT $number ";

你应该逃避你的变量
查询应按此顺序排列：SELECT，FROM，WHERE，ORDER BY和LIMIT：

在ORDER BY语句中使用php变量会产生错误

3 个答案: