I have a multiple line string like following:
END IF;
EXECUTE IMMEDIATE \' CREATE INDEX #idx1
ON somename ( row
(?m) makes the regex multiline - allows you to match beginning (^) and end ($) of string operators (in this case, to match the beginnings and ends of individual lines, rather than the whole string):
/(?m)(EXECUTE).*?;/
(?s) - dotall flag - makes the regex match newlines with . (dot) operators:
/(?s)(EXECUTE).*?;/