Converting Raw(16) to GUID
A RAW(16) basically is a GUID: it's a 16-byte hex value. So one option is to just leave it alone. Oracle will implicitly cast between character and hex, so if you're looking for a row whose raw value is FE2BF132638011E3A647F0DEF1FEB9E8, you can use a string in your query:
SELECT *FROM myTableWHERE myRaw16Column = 'FE2BF132638011E3A647F0DEF1FEB9E8';If you want to change the RAW(16) to CHAR(32) for your conversion you can use RAWTOHEX as @tbone suggests.
INSERT INTO NewTable (myGUIDColumn, ...) SELECT RAWTOHEX(myRawColumn), ... FROM OldTableIf you want to make it a CHAR(36) dash-formatted GUID, things get complicated quickly:
INSERT INTO NewTable (myGUIDColumn, ...) SELECT REGEXP_REPLACE(myRaw16Column, '(.{8})(.{4})(.{4})(.{4})(.*)', '\1-\2-\3-\4-\5'), ... FROM OldTable