Loop query with different value - php

Question

I have a table schedules that contains sched_id, sc_id1, sc_id2, sc_id3, sc_id4, sc_id5, sc_id6, sc_id7, sc_id8, sc_id9, sc_id10, sched_name.
I have also table subject_current that has sc_id, sl_id, schoolyear, semister, etc... sc_id1 - scid10 is a "foreign key" from sc_id of table subject_current
Also, I have a table subject_list with sl_id, subject_code, subject_description, subject_prereq. sl_id from table subject_current is a "foreign key" from sl_id of table subject_list.
Now, what I want to do is to "echo" the subject_description from table subject_list only giving me the value of sc_id1 - sc_id10 from table schedules.
This code doesn't work:
for($jaa = 1;$jaa < 11;$jaa++){
$s_scid = "s_scid".$jaa;
$s_sublist = mysql_query("SELECT * FROM subject_current WHERE sc_id='$s_scid'");
while($rows_ss = mysql_fetch_assoc($s_sublist)){
$ss_slid = $rows_ss['sl_id'];
$ssl_sublist = mysql_query("SELECT * FROM subject_list WHERE sl_id='$ss_slid'");
while($rows_ssl = mysql_fetch_assoc($ssl_sublist)){
$ssl_slid = $rows_ssl['sl_id'];
$ssl_subdesc = $rows_ssl['subject_description'];
}
}
echo $ssl_subdesc;
}
EDIT
This is what I want to exactly happen:
$s_scid1 = $rows_s['sc_id1']; // which is a value of 1
$s_scid2 = $rows_s['sc_id2']; // which is a value of 2
$s_sublist = mysql_query("SELECT * FROM subject_current WHERE sc_id='$s_scid1'");
while($rows_ss = mysql_fetch_assoc($s_sublist)){
$ss_slid1 = $rows_ss['sl_id'];
$ssl_sublist = mysql_query("SELECT * FROM subject_list WHERE sl_id='$ss_slid1'");
while($rows_ssl = mysql_fetch_assoc($ssl_sublist)){
$ssl_slid1 = $rows_ssl['sl_id'];
$ssl_subdesc1 = $rows_ssl['subject_description'];
echo $ssl_subdesc1;
}
}
$s_sublist2 = mysql_query("SELECT * FROM subject_current WHERE sc_id='$s_scid2'");
while($rows_ss2 = mysql_fetch_assoc($s_sublist2)){
$ss_slid2 = $rows_ss2['sl_id'];
$ssl_sublist2 = mysql_query("SELECT * FROM subject_list WHERE sl_id='$ss_slid2'");
while($rows_ssl2 = mysql_fetch_assoc($ssl_sublist2)){
$ssl_slid2 = $rows_ssl2['sl_id'];
$ssl_subdesc2 = $rows_ssl2['subject_description'];
echo $ssl_subdesc2;
}
}
This is a pain to write it 10 times. So I want to loop it. But someone told me it's bad and told me about INNER JOIN. But how can I with INNER JOIN?

Answer 1

The way you describe it, you should do something like:
for($jaa = 1;$jaa < 11;$jaa++){
$s_scid = "s_scid".$jaa;
$the_query = "SELECT sl_id, subject_description FROM subject_list sl JOIN subject_current sc ON sl.sl_id=sc.$s_scid";
/* the above should generate a JOIN with a particular element from your master table */
$ssl_sublist = mysql_query($the_query);
while($rows_ssl = mysql_fetch_assoc($ssl_sublist)){
$ssl_slid = $rows_ssl['sl_id'];
$ssl_subdesc = $rows_ssl['subject_description'];
echo $ssl_subdesc;
}
}