Order by "count (columns not null)"

I'm looking at a way to order the MySQL results by a count of the columns where the value is not null. Therefore,

[id] [1] [1] [0] [1] [1] = 4

[id] [0] [1] [1] [1] [0] = 3

[id] [0] [0] [0] [1] [1] = 2

[id] [1] [0] [0] [0] [0] = 1

In the above case I'm ignoring the ID column but in practice I wouldn't care. ID is always NOT NULL so adding it to count wouldn't change the results.

Anyone have any idea on this that d开发者_如何学Gooesn't involve doing a PHP parse on the result into a new array? I'm trying to keep the processing portion in the DB level.

ORDER BY IF(`a` IS NULL, 0, 1) + IF(`b` IS NULL, 0, 1) ... DESC

Where a, b, ... is the names of fields (yes, you need to enumerate them all manually)

PS: if you don't know the difference between 0 and NULL this:

ORDER BY `a` + `b` ... DESC

will be good enough for you