Question

There are 6 possible keys in a MySQL field. Lets call them types. Through PHP, I have defined an array, that is called $order, and arranges these types in order I want them to appear.

There is a table, articles, which has a field articles.type . Any article can have 0-6 types added to it. Now, what I want to do, is grab all of the articles, and order them from the prototype. What is the best way to do this? Can this be done in MySQL, since I suppose that would be faster? And if not, how can it be done in PHP?

Example:

Table:

id     articleId     type
1      3             type1
2      3             type2
3      3             type3
4      3             type4
5      4             type5
6      4             type6
7      5             type5
8      7             type1
9      7             type5

Order:

$order=array('type1','type2','type3','type4','type5','type6');

How do I fetch the results ordered by my $order variable?

Answer 1

You’d need to massage that array into a mysql-style if/case statement:

$order_by = "ORDER BY CASE";
$pos = 1;
foreach ($order as $clause) {
   $order_by .= " CASE `type`='$clause' THEN " . $pos++;
}
$order_by .= " ELSE " . $pos++;

which would generate something like

ORDER BY CASE
   WHEN `type`='type1' THEN 1
   WHEN 'type`='type2' THEN 2
   ...
   ELSE n