Converting json in oracle 12c

--STEP1 CREATE TABLE C##MREPUSER2.TWEETS2 AS select SUBSTRB(DBMS_LOB.SUBSTR(RAWSOURCE, 3500 , 1), 1,4000) AS RAWSOURCE1 , T.* FROM CT --STEP2 SELECT REPLACE(REPLACE(REPLACE(trim(SUBSTR(RAWSOURCE1,INSTR(RAWSOURCE1,&"created_at": "'), INSTR(RAWSOURCE1,&"id": &"created_at": "&"& created_at, RAWSOURCE1 FROM C##MREPUSER2.TWEETS2