I have one column which contain 6 character(post code), the first, third, fifth is letter and second, forth and sixth is number,how to get them(post code) from each string with sql query, thanks in advance.

for example:
we have address column which contain a long string like this:

1111streetuniversityapp3h1p2w3montrealquebeccanada

we need take h1p2w3 out, which is post code.