Form insert a string of values based on check for record

i have this code


  • Selecting a field from another table

// Check for record
$check_sql = “SELECT project_opleidingen.op_id”
. " FROM project_opleidingen,
. " WHERE FIND_IN_SET(project_opleidingen.op_crebo,ILP_rooster_TEMP.wk_ex_mail_1) AND
(ILP_rooster_TEMP.wk_id = {wk_id})";
sc_lookup(rs, $check_sql);

if (isset({rs[0][0]})) // Row found
{wk_op_id_koppel} = {rs[0][0]};

else // No row found

work fine, but gives only one record back. there are seven records that match this criteria. how can i get all 7 and put them in a comma seperated string?