How to count instances of character in SQL Column

Question

I have an sql column that is a string of 100 \'Y\' or \'N\' characters. For example:

YYNYNYYNNNYYNY...

What is the easiest way

Answer 1

The second answer provided by nickf is very clever. However, it only works for a character length of the target sub-string of 1 and ignores spaces. Specifically, there were two leading spaces in my data, which SQL helpfully removes (I didn't know this) when all the characters on the right-hand-side are removed. Which meant that

" John Smith"

generated 12 using Nickf's method, whereas:

" Joe Bloggs, John Smith"

generated 10, and

" Joe Bloggs, John Smith, John Smith"

Generated 20.

I've therefore modified the solution slightly to the following, which works for me:

Select (len(replace(Sales_Reps,' ',''))- len(replace((replace(Sales_Reps, ' ','')),'JohnSmith','')))/9 as Count_JS

I'm sure someone can think of a better way of doing it!