我想检查表中是否已有值。
我桌子的结构是这样的:
ApplicantId = INT
EventId = INT
StudentId = INT
无需使用unique,因为这些表具有依赖关系。
以下是我到目前为止所尝试的内容:
include('../connectdb.php');
$ScholarPointId = $_GET["ScholarPointId"];
$Point = $_GET["Point"];
$ScholarId = $_GET["ScholarId"];
$EventId = $_GET["EventId"];
$verifysql = mysql_query("SELECT EventId FROM scholar_attended_events WHERE ScholarId ='$ScholarId' ");
#$resultVerify = mysql_fetch_assoc($verifysql);
$num_rows = mysql_num_rows($verifysql);
if( $num_rows > 0 )
{
$script = "<script>
alert('The user has already attended this event!');
</script>";
header('updatescholarpoints.php');
exit();
}
else{
$result = mysql_query("UPDATE scholar_points
SET scholar_points.Points =
scholar_points.Points + $Point
WHERE scholar_points.ScholarPointId = '$ScholarPointId' ") or die(mysql_error());
mysql_query("INSERT INTO scholar_attended_events (EventId , ScholarId) VALUES( '$EventId' , '$ScholarId' ) ")
or die(mysql_error());
}
?>
我想要的是检查Student = StudentId是否已经使用了EventId。如果是,则系统将提示警告框。否则,更新并插入相应的表中。我怎样才能做到这一点?我好像在这里想念一些东西。如果你能提供帮助,我真的很感激。
答案 0 :(得分:1)
错过了=
?
$verifysql = mysql_query("SELECT EventId FROM scholar_attended_events WHERE ScholarId =$ScholarId ");
(并使用PDO或mysqli,您的代码实际上处于弃用状态)