SELECT case when charindex('12',s) =0 then 0 else length(s)-charindex(reverse('12'),reverse(s)) end AS lastIndexOf, s FROM t;
The above was not tested.
The above finds the last index of '12' in column 's' of table 't'.
Hope this helps.

This might be a little "simpler"

(CHARINDEX('.',REVERSE(ContactEmail)) > 4)

This checks for the last index of a period in an email address thats position is not more than 3 places in

meme.email@domain.ccom would "fail", but meme.email@domain.com and meme.email@domain.ca would "pass"

Adam,

The solution you posted works only when the string to search consists of exactly one character.
When a longer string is needed you need to reverse both, as in my answer #1.

Don't you agree?

Dimitar