如何选择并查看是否有记录？

Question

$sql=mysql_query("SELECT day='$day','$month' day='$day' year='$year' FROM punchin WHERE pass='$pass' '$month' AND day='$day' AND year='$year' ");


if (mysql_num_rows($sql) === 0) {
mysql_query( "INSERT INTO punchin (count,pass,month,day,year,time,wday) values (null,'$pass','$month','$day','$year','$time','$wday')") or die(mysql_error());
t 

}else
        echo "<a href='loginoption.php'>You can only punch-in once a day!</a>";

问题是...... 员工每天只能打一次，但这个人可以随时打卡。

Answer 1

您的SELECT查询中存在问题，请尝试使用：

$sql=mysql_query("SELECT day FROM punchin WHERE pass='$pass' AND month = '$month' AND day='$day' AND year='$year'");

if (mysql_num_rows($sql) == 0) {
mysql_query( "INSERT INTO punchin (count,pass,month,day,year,time,wday) values (null,'$pass','$month','$day','$year','$time','$wday')") or die(mysql_error());

}else
        echo "<a href='loginoption.php'>You can only punch-in once a day!</a>";