Calculating the number of occurances of a character/string inside a string

How can we find number of occurances of a particular string in another string? For example in SQLServer, how can we find number of occurances of 'e'? Its a simple but interesting logic

DECLARE @String AS VARCHAR(MAX) = 'SQLServer'
,@SearchString AS VARCHAR(MAX) = 'e'

SELECT (LEN(@String) - LEN(REPLACE(@String,@SearchString,'')))/LEN(@SearchString)

So simple. First take the actual string. Replace the string with nothing by replace function and using search string and divide the whole value with the length of search string.