How to stop echo data multiple times

Question

I am trying to get data from multiple tables and I got them while fetching data I am getting same data multiple time

<?php
$stmt = $DB_con->prepare('SELECT t1.id,t2.id from t1,t2ORDER BY t1.id DESC ');
$stmt->execute();   
if($stmt->rowCount() > 0){
    while($row=$stmt->fetch(PDO::FETCH_ASSOC)){
        extract($row);
}
?>

This I am getting data but multiple times like t1 have 10 ids t2 have 20 ids so I got 30 IDs on the display

show your schema, show your expected out put. May be you need to use `JOIN` — B. Desai, Mar 31 '18 at 09:10
Always add all question details to your question as an Edit. Please delete your comments that contain question details. I think you will want a different JOIN. — mickmackusa, Mar 31 '18 at 09:37
Time to research the different JOINs. https://stackoverflow.com/questions/5294311/difference-between-these-two-joining-table-approaches — mickmackusa, Mar 31 '18 at 09:41
update your question add a real data sample and the expcted .. result .. — ScaisEdge, Mar 31 '18 at 09:45

score 0 · Answer 1 · answered Mar 31 '18 at 09:49

for avoid duplicated rows you could use distinct

  $DB_con->prepare('SELECT DISTINCT  t1.id,t2.id from t1,t2 ORDER BY t1.id DESC ');

but in your FROM clause you are using a cross join (a cartesian product between each row of a table multiplied by each row for other table)

could be you need a join alia a condition between tables column thate relate the tow table ed.

  $DB_con->prepare('SELECT DISTINCT  t1.id,t2.id 
  from t1
  INNER JOIN t2 ON t1.id = t2.id ORDER BY t1.id DESC ');

the join based on t1.id = t2.id is just a sample you should check for the evnetual real joining condition

How to stop echo data multiple times

1 Answers1