Question

我正在尝试使用PHP在MySQL中选择年份：

session_start();
$school_id = $_SESSION['school_id'];
$section_id = $_POST['section_id'];
$today  = date("Y");

$select_grades_deped = "SELECT * 
             FROM deped_grade_archive 
             WHERE school_id='$school_id'
             AND section_id='$section_id'
             AND year(submission_date) ='$today' ";

$query_check_grades= mysql_query($select_grades_deped) or die (mysql_error());

$check_count = mysql_num_rows($query_check_grades);

if($check_count == 0){
    $return['checked'] = "0";
}
else{
    $return['checked'] = "1";
}

echo json_encode($return);

但不幸的是，当我尝试以下内容时：

SELECT year( submission_date )
FROM deped_grade_archive
WHERE school_id = '$school_id'
AND section_id = '$section_id'

它从我的表中返回零值。我将submission_date的数据类型更改为date数据类型，因为它之前是varchar，但仍然没有用。请帮帮我们。

Answer 1

将其更改为date数据类型时，如果未设置列的默认值（例如CURRENT_TIMESTAMP），则值为0000-00-00。因此，YEAR操作将返回0，如图所示。

您需要将submission_date列更新为您希望为每行指定的时间。

Answer 2

尝试就好了

           SELECT YEAR('submission_date')

ref

从mysql中的日期选择年份时的零值

2 个答案: