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

Here's what I used in Oracle SQL to see if someone was passing a correctly formatted phone number:

WHERE REPLACE(TRANSLATE('555-555-1212','0123456789-','00000000000'),'0','') IS NULL AND
LENGTH(REPLACE(TRANSLATE('555-555-1212','0123456789','0000000000'),'0','')) = 2

The first part checks to see if the phone number has only numbers and the hyphen and the second part checks to see that the phone number has only two hyphens.