Save PHP ForEach Loop value in a Variable as Comma Separated String

Question

I am Trying to Save Foreach Loop value in a Variable as comma separated.For this I have below code so far.It is getting all the values in a list but without Comma. How can I insert Comma after each id

$stmt = $con->query($sql);  
$tmp = '';

foreach ($stmt as $row)
{
  $user_id=$row['user_id'];
  $tmp .= $row['user_id']; 
}

echo $tmp;

Well, have you tried actually putting a comma in the string? You seem to know how to concatenate string, so I'm not really sure what problem you're having. You haven't made any attempt to add a comma here. — Patrick Q
– Patrick Q, Commented Mar 30, 2020 at 14:38
@AbraCadaver Would have to be combined with php.net/manual/en/function.array-column.php — Patrick Q
– Patrick Q, Commented Mar 30, 2020 at 14:42
@roy Please describe in what way it was not working. What was the result of that attempt and how did it differ from your desired result? — Patrick Q
– Patrick Q, Commented Mar 30, 2020 at 14:43

RiggsFolly · Accepted Answer · 2020-03-30 15:41:47Z

3

Simply concatenate a comma onto the id, each time you add to the $tmp variable.

$stmt = $con->query($sql);  
$tmp = '';

foreach ($stmt as $row){
  $tmp .= $row['user_id'] . ','; 
}
$tmp = trim($tmp, ',');    // remove trailing comma
echo $tmp;

In answer to your comment:

$v=trim($tmp, ','); 
$insert = $con->prepare("INSERT INTO $dtBe
                        (user_mobile,user_id,posting_date) 
                VALUES ('$umobile',$v,'$posting_date')"); 
$insert->execute();

But there is no benefit or security in preparing a query when you have already concatentated values into.

So use a proper prepared and bound approach.

$v=trim($tmp, ','); 
$insert = $con->prepare("INSERT INTO $dtBe
                        (user_mobile,user_id,posting_date) 
                VALUES (?,?,?)"); 
$insert->bind_param('sss', $umobile, $v,$posting_date);
$insert->execute();

edited Mar 30, 2020 at 15:41

answered Mar 30, 2020 at 14:49

RiggsFolly

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12 Comments

roy Over a year ago

hi it is outputting the result as comma separated but now I am getting the error while inserting the comma separated value , below is my insert statement which was working earlier without this comma separated value

$v=trim($tmp, ','); $insert = $con->prepare("INSERT INTO $dtBe(user_mobile,user_id,posting_date)      VALUES ('$umobile',$v,'$posting_date')");          $insert2->execute();

it is giving error call to a member function on boolean

RiggsFolly Over a year ago

Issue is you need to wrap $v in quotes as it is a string now there are commas in it so '$v'

RiggsFolly Over a year ago

But if you are preparing that query, and you should be, then you should also be binding the values to ? parameters as well. There is no safety in preparing a query that you have already concatenated dangerous values into

Patrick Q Over a year ago

@roy Are you intending to insert a list of ids into the user_id column or a single id? It is not clear. I think you should really update your question (or delete and post a new one) to better describe what your ultimate goal is here. Most likely, your approach as a whole is wrong (or at least not optimal) and getting a better picture of what's going on could help us suggest a better way to achieve your goal.

RiggsFolly Over a year ago

It is almost never a good idea to put comma delimited lists of ids into a rows column. It makes using that information very difficult later in raw SQL

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