How to count the number of times a character appears in a SQL column?
SELECT LEN(RequestedReportParams) - LEN(REPLACE(RequestedReportParams, ',', ''))
FROM YourTable
WHERE .....
This is simply comparing the length of the column with the commas, with the length of the value with the commas removed, to give you the difference (i.e. the number of commas)
It seems the quick and dirty way to answer the question you've been asked would be to do this:
select
count(*) as cnt
FROM
[table]
WHERE
RequestedReportParams Like '%,%,%'