Question

I need to order some information with order by in a MySQL query. Is there a possibility to use the ABS function only if the first char is numeric?

Pseudo example:

SELECT * FROM table 
ORDER BY
(( name[0] = numeric ) ? ABS(name) : name)
ASC

---

Thanks for the answers so far, tried a lot with your answers but I don’t get the result I want.

The current code:

<?php
$filters = $this->db->query("
    SELECT
        tb_spec_feature.feature_id,
        tb_spec_feature.name
    FROM
        tb_spec_feature
    WHERE
        filter=1
");
$filters = $filters->result_array();
foreach($filters as $key=>$filter)
{
    $filters_sub = $this->db->query("
        SELECT DISTINCT
            tb_spec_value.value_id,
            tb_spec_value.name as value_name,
            tb_spec_sign.name as sign_name
        FROM
            tb_spec_fk
        INNER JOIN
            tb_spec_value
        ON
            tb_spec_value.value_id = tb_spec_fk.value
        LEFT JOIN
            tb_spec_sign
        ON
            tb_spec_sign.sign_id = tb_spec_fk.sign
        WHERE
            feature=".$this->db->escape($filter['feature_id'])."
        ORDER BY
            ABS(tb_spec_value.name) ASC
    ");
    $filters[$key]['values'] = $filters_sub->result_array();
}
?>

This will output (tb_spec_feature.name and then the tb_spec_value.name):

Screen inches

• 7
• 7.7
• 7.9
• 8.9
• 9.7
• 10
• 10.1
• 12.1

Resolution

• 800 x 480
• 1024 x 600
• 1024 x 768
• 1280 x 800
• 1280 x 768
• 1920 x 1200
• 2048 x 1536

Operating system

• Android 3.1
• Android
• BlackBerry Tablet OS
• Android 3.2
• Android 2.3
• Android 4.0
• iOS 5
• Android 4.0.3
• iOS 4
• Android 2.2
• Windows 7 Professional
• Windows 8
• Windows 8 Pro
• iOS 6

As you can see the inches and resolutions are okay, but the operating systems aren’t ordered well. If I remove the ABS the result will be:

Screen inches

• 10
• 10.1
• 12.1
• 7
• 7.7
• 7.9
• 8.9
• 9.7

Resolution

• 1024 x 600
• 1024 x 768
• 1280 x 768
• 1280 x 800
• 1366 x 768
• 1920 x 1200
• 2048 x 1536
• 800 x 480

Operating system

• Android
• Android 2.2
• Android 2.3
• Android 3.1
• Android 3.2
• Android 4.0
• Android 4.0.3
• BlackBerry Tablet OS
• iOS 4
• iOS 5
• iOS 6
• Windows 7 Professional
• Windows 8
• Windows 8 Pro

As you can see now, the operating systems are ordered well but the inches and resolutions not.. I hope somebody can help me out 🙂

Answer 1

This code is the MySql way of your question:

SELECT * FROM table 
ORDER BY
CASE WHEN LEFT(name, 1)>='0' AND LEFT(name, 1)<='9' THEN ABS(name) 
     ELSE name 
     END ASC

(Edit)
But according to comments, is better for you:

ORDER BY ABS(name), name

That works in this way:
If ABS() can be applied to ‘name’ the numeric resulting value will be ordered, but in the opposite case, if ABS(name) evaluates to null (because a non numeric has no abs value) then the second field (name) on order by, is which is relevant to the sort.