How to convert dates in odd format to months

[lokhtar]

So I have a column called 'age' in my sql column that is inconsistent in format. It lists ages of kids in days, weeks or months. For example:

Output:
0d
6d
7d
1w, 3d
7w, 5d
4m
5m

What I want to do is convert that into months, like, anyone under 30 days would be 0 months, anyone between 1-2 months would be 1 month, etc. The max-age I have is seven months, so it would be changed to one of eight categories: 0,1,2,3,4,5,6,7.

I was thinking of a clunky way of doing it, like searching to see if there is a 'w', and if so, remove the w and everything after the w, and take that number. Do the same for days, and then for months. But I am sure there has to be a cleaner way?