oracle 12c - select string after last occurrence of a character

Question

I have below string:

ThisSentence.ShouldBe.SplitAfterLastPeriod.Sentence

So I want to select Sentence since it is the string a

Answer 1

how many dots in a string?

select length(str) - length(replace(str, '.', '') number_of_dots from ...

get substring after last dot:

select substr(str, instr(str, '.', 1, number_of_dots)+1) from ...