联接3个表时无法查看结果

Question

I have some trouble when I Joining 3 tables, I use mysqli procedural. here's my query..

$select = $connection->conn->query('SELECT * FROM master_beli, supplier, karyawan WHERE supplier.id_supplier = master_beli.id_supplier AND karyawan.id_karyawan = master_beli.id_karyawan');

After that I viewing with this code

while($fetchData = $select->fetch_array()){
   echo $fetchData['id_karyawan'].'<br>';
}

I don't know where the problem is, because I use this query a few months ago and it's worked, but now isn't work..

Answer 1

SELECT  master_beli.id_supplier,master_beli.id_karyawan
 FROM master_beli
 join supplier  on supplier.id_supplier = master_beli.id_supplier
 join karyawan on karyawan.id_karyawan = master_beli.id_karyawan;

it work on mysql

Answer 2

Could be your issue is related to the ambiguity of the column name id_karyawan present in two tables try use an explicit alias or a explict column naming eg :

$select = $connection->conn->query('SELECT master_beli.id_karyawan
      FROM master_beli
      INNER JOIN supplier ON supplier.id_supplier = master_beli.id_supplier 
      INNER JOIN karyawan ON  karyawan.id_karyawan = master_beli.id_karyawan');

and as suggested in the code above you should use explicit join sintax ..for better readibilty (the use of implict join sintax is not more promoted in sql)