mysql sum() is not working. How can I solve it?

Question

I am using php 7.2...

The code is working fine

<?php 

    $add=mysqli_query($conn,'SELECT ac_id, SUM(amount)  from stac where ac_id="117" '); 
    while($row1=mysqli_fetch_array($add)) { $mark=$row1['SUM(amount)'];  
    echo $mark ; }?>

but the code below is not working. Please help me.

<?php 
  $ac_id=$_POST['ac_id'];


    $add=mysqli_query($conn,'SELECT ac_id, SUM(amount)  from stac where ac_id=$ac_id '); 
    while($row1=mysqli_fetch_array($add)) { $mark=$row1['SUM(amount)'];  
    echo $mark ; }?>

What about it isn't working? Have you checked for [mysqli errors](http://php.net/manual/en/mysqli.error.php)? By the way, if you're going to use variables, you really ought to use [prepared statements](http://php.net/manual/en/mysqli.quickstart.prepared-statements.php). It will save on quoting headaches. — aynber, May 08 '18 at 13:30
have your query like this SELECT ac_id, SUM(amount) as sum_val from stac where ac_id=$ac_id and use sum_val as key in php array — ManiMuthuPandi, May 08 '18 at 13:31
If the column is varchar, you can't SUM on that. You would need to cast it. — Funk Forty Niner, May 08 '18 at 13:33

score 0 · Answer 1 · answered May 08 '18 at 13:30

Its seems like your id field is not integer so you should pass variable into single quote (') and also pass your query in double quote (") so variable will parse correctly.

Replace your query with this

$add=mysqli_query($conn,"SELECT ac_id, SUM(amount)  from stac where ac_id='$ac_id' ");

score 0 · Answer 2 · answered May 08 '18 at 13:34

0

Did you forget to add the group by when using an aggregate? Like so:

 SELECT ac_id, SUM(amount)  from stac where ac_id=$ac_id group by ac_id

answered May 08 '18 at 13:34

Claudiu Haidu

817
4
12
24

score -1 · Answer 3 · answered May 08 '18 at 13:30

-1

Try changing your query to

$add=mysqli_query($conn,"SELECT ac_id, SUM(amount)  from stac where ac_id='$ac_id' ");

answered May 08 '18 at 13:30

Maaz Ali

83
5

mysql sum() is not working. How can I solve it?

3 Answers3