How to output items in Order in MySQL?

Question

I have a column called "menu_order" which has no default value. When I select the contents of this column using the following select statement:

SELECT * FROM categories ORDER BY menu_order ASC

It lists the category items that have nothing as their menu order first and then the one's that have 1's and 2's and 3's. Is there any way to prevent SQL from take nothing to come before numbers when I am trying to list things in order?

So for example, if I have:

cat_name | menu_order
----------------------
Lunch    | 1
Dinner   | 

And I perform my query, the output should be:

Lunch Dinner

Not:

Dinner Lunch

Answer 1

This will put the null values last:

SELECT *
FROM categories
ORDER BY menu_order IS NULL ASC, menu_order ASC

Answer 2

You can use the IFNULL function in the order by with a large number

ORDER BY IFNULL(menu_order, 1000) ASC 

You can even try using a case statement

ORDER BY 
CASE 
    WHEN menu_order IS NULL THEN 1
    ELSE 0
END ASC,
menu_order ASC

Answer 3

ORDER BY IFNULL(menu_order, 99999999) ASC