Running a select on a list of comma separated values in PHP

Question

I am having a bit of a problem running a select query on a database. Some of the data is held as a list of comma separated values, an example:

Table: example_tbl
| Id | People | Children |
| 1  | 1,2,3  |  8,10,3  |
| 2  | 7,6,12 |  18,19,2 |

And an example of the kind of thing I am trying to run:

<?php
    include 'class.php';
    $selection = 1;
    $db = new DbClass;
    $tbl_name = 'example_tbl';
    $sql = "SELECT * FROM $tbl_name WHERE ".$selection." IN People";
    $result = $db->query($sql);
    $print_r($result);
?>

The script above should return row 1 after finding a '1' in the People column but clearly I have mucked it up.

The issue I am having is that I think I have the IN statement backwards, i.e. I THINK this method would be to select values if $selection was a comma separated (imploded) list, rather than the way round I am trying to use it.

I don't know if it's too important about what I am sending and receiving from the db class above, but if you wanted to know, it's just a simple script that runs all relevant bits and returns an array of the result. at the moment it's returning nothing because it's not finding a match

Thanks in advance for anything you can tell me.

Cheers -Dave

Answer 1

Why do people insist on this insane habit of comma-separated data values in a column rather than properly normalising their database design. It always leads to problems.

SELECT * 
  FROM $tbl_name 
 WHERE CONCAT(',',People,',') LIKE '%,".$selection.",%'";

or

SELECT * 
  FROM $tbl_name 
 WHERE FIND_IN_SET(".$selection.",People);