它说1条记录添加了但是数据库表有什么解决方案呢？

this is an redirect page for form.this form will allow user to choose there group and database will store data into tables of selected groups.
include'connection.php';

   if (isset($_POST['member']))
    {
    if (intval($_POST['member']) === Staff)
    {

        $insert1=mysql_query("INSERT INTO tblstaff(ST_Fname,ST_Sname,ST_Gender) VALUES``
                            ('$_POST[firstname]','$_POST[surname]','$_POST[sex]')");
    }
    else if (intval($_POST['member']) === Tutor)
    {
        $insert2=mysql_query( "INSERT INTO tbltutor(Tutor_Fname,Tutor_Sname,Tutor_Gender) VALUES
                     ('$_POST[firstname]','$_POST[surname]','$_POST[sex]')");
    }
    else if (intval($_POST['member']) === Student)

    {
        $insert3= mysql_query("INSERT INTO tblstudent(STU_Fname,STU_Sname,STU_Gender) VALUES ('$_POST[firstname]','$_POST[surname]','$_POST[sex]')");
    }
    else
    {
        if (!mysql_query() === false)
                   {
                           die('Error: ' . mysql_error());
                     }
                     else
                               echo "1 record added";


    }
}

its saying 1 record added but its not adding any data into database.

This is how you test for success:

if (!mysql_query() === false) {
    die('Error: ' . mysql_error());
} else
    echo "1 record added";

And this is how mysql_query() is documented:

For other type of SQL statements, INSERT, UPDATE, DELETE, DROP, etc, mysql_query() returns TRUE on success or FALSE on error.

For some reason, you are expecting reverse return values: TRUE on error, FALSE on success.

P.S. Please indent your code properly!

try the following

if (isset($_POST['member']))
    {
     $insert = false;
    if (intval($_POST['member']) === Staff)
    {

        $insert=mysql_query("INSERT INTO tblstaff(ST_Fname,ST_Sname,ST_Gender) VALUES``
                            ('$_POST[firstname]','$_POST[surname]','$_POST[sex]')");
    }
    else if (intval($_POST['member']) === Tutor)
    {
        $insert=mysql_query( "INSERT INTO tbltutor(Tutor_Fname,Tutor_Sname,Tutor_Gender) VALUES
                     ('$_POST[firstname]','$_POST[surname]','$_POST[sex]')");
    }
    else if (intval($_POST['member']) === Student)

    {
        $insert= mysql_query("INSERT INTO tblstudent(STU_Fname,STU_Sname,STU_Gender) VALUES ('$_POST[firstname]','$_POST[surname]','$_POST[sex]')");
    }
        if (!$insert)
                   {
                           die('Error: ' . mysql_error());
                     }
                     else
                               echo "1 record added";



}