Question

Just asking is it possible in php to perform sql statment’s in 1 function.

What my sql really does is fetch data from three tables in my database.
I am currently unsure of what method to use. Inner join would pop into it but i forgot what the proper syntax. so i was thinking about this.

$qry_display = "SELECT student_id,
section_id,level,photo,address,father_occupation,father_phone,father_company,mother_occupation,
mother_phone,mother_company 
from tbl_er 
where student_id='$id' AND level="3rd Year"";

The above statement would retrieve the information from tbl_er these would be the students history.

$qry_display = "SELECT fname,
sex,
lname,
mname,
birth_date,
birth_place,
address,
father,
father_degree,
mother,
mother_degree,
from tbl_enroll where student_id='$id'";

The above statement would retrieve part of the information from tbl_enroll these would be the students core unchangeable data. Also the first statement has “section_id” to be retrieved. so my idea is to retrieve that value so it would be used for the last sql which is.

$qry_display = "SELECT section_name,adviser_id,schoolyr 
from tbl_section 
where student_id='$id' AND section_id='$sid'";

and my idea to on how to get the section_id is before the last statement i would put.

    $sid= section_id  (I am unsure if this will work.)

Also will this statement trigger all three statements in one function?

        $sql_display = mysql_query($qry_display) or die (mysql_error());

Thank you, Appreciate any feedback.

Answer 1

There is a lot wrong with this, and you probably will not get what you are looking for even if you work out the bugs, so lets start with writing this as 1 coherent query with left joins (good call btw).

$qry_display = "SELECT
            a.student_id, a.section_id, a.level, a.photo, a.address, a.father_occupation, a.father_phone, a.father_company, a.mother_occupation, a.mother_phone, a.mother_company,
            b.fname, b.sex, b.lname, b.mname, b.birth_date, b.birth_place, b.address, b.father, b.father_degree, b.mother, b.mother_degree,
            c.section_name, c.adviser_id, c.schoolyr
            FROM tbl_er AS a
            LEFT OUTER JOIN tbl_enroll AS b ON a.student_id = b.student_id
            LEFT OUTER JOIN tbl_section AS c ON a.section_id = c.section_id
            WHERE a.student_id=".$id." AND a.level='3rd Year'";

The last join doesn’t care about the student_id because the section / advisor relationship does not depend on a student.