How to SELECT same IDs from database which are stored in Array?

Question

I have stored IDs as STRING of users who rated a post. Example:

$ids="5,8,4,9,7,8,87";

and I later convert the string into an array:

$kaboom = explode(',',$ids);

Now I want to query another table and select all field where the id is found in array $kaboom. I tried but I get the following error:

Notice: Array to string conversion in C:\xampp\htdocs\cebs\include\post_reacts.php on line 22

This is my code:

<?php
//include connection file
include 'dbc.php';


if(isset($_POST['post_id'])){
$post_id = $_POST['post_id'];

//SELECT ALL IDS OF THOSE WHO RATED THE POST

$query = mysqli_query($dbc_conn,"SELECT highlight_voters FROM $public_feed_table WHERE id='$post_id' LIMIT 1");

if($query==true){

while($row=mysqli_fetch_assoc($query)){
$ids = $row['highlight_voters'];
$kaboom = explode(",",$ids);


//select IDS which is/are in array and and get details about the ID

$check_ids_which_in_array = mysqli_query($dbc_conn,"SELECT * FROM $table_name WHERE id='$kaboom' ");

}

if($check_ids_which_in_array==true){
while($b=mysqli_fetch_assoc($check_ids_which_in_array)){
$person_who_rated =$b['id'];

    //do something here after...
        }

    }               
}
}
?>

@Mihai: I think that should be WHERE ids IN ($ids) - $kaboom is the exploded version, which would be cast back to the string Array anyway. — halfer
– halfer, Commented Apr 3, 2016 at 16:50
OP, just be careful that $ids is not tainted - if it comes from the user then you will have to explode it, clean it, and implode it again. — halfer
– halfer, Commented Apr 3, 2016 at 16:51

bytecode77 · Accepted Answer · 2016-04-03 16:53:27Z

3

You can use IN(...)

mysqli_query($dbc_conn, "SELECT * FROM $table_name WHERE id IN($ids)")

A query that uses IN would look like this:

SELECT * FROM table WHERE id IN(1, 2, 3, 7, 8, 9)

Therefore, you don't need to explode into an array beforehand.

edited Apr 3, 2016 at 16:53

answered Apr 3, 2016 at 16:52

bytecode77

15k31 gold badges119 silver badges151 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

James Favour Over a year ago

So this means if i was gonna use the explode then i will have to implode and push it back into a string which is not necessary in this case.

bytecode77 Over a year ago

If you already have a comma separated string of ID's, then nothing else is required. You can just put it in the query as it is.

halfer Over a year ago

@bytecode77: bear in mind that if the CSV string comes from user input, then putting it in the query as it is is a security risk. It's not clear if it is tainted in this case.

bytecode77 Over a year ago

I know that. But it's not related to the OP's question and problem. It's a different problem.

Collectives™ on Stack Overflow

How to SELECT same IDs from database which are stored in Array?

1 Answer 1

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related