SQL tuning question

Dear All

Thanks for taking time to read tihs post, I apologise in advance as i am bit naive when it comes to query rewriting.

Below is the query, I ran for sql tuning:

SELECT CONTAINER_ID

FROM (

SELECT CF.CONTAINER_ID

FROM CONTEXTS CTXTS , CONTEXT_FOLDERS CF ,

(SELECT COLUMN_VALUE CONTAINER_ID

FROM TABLE(CAST(:B1 AS STRING_GUID_ARRAY))) SRC

WHERE CTXTS.CONTAINER_ID = SRC.CONTAINER_ID AND CTXTS.PERSONAL = '0' AND CTXTS.CONTAINER_ID = CF.CONTEXT_CONTAINER_ID AND CF.DEFAULT_CONTEXT_FOLDER = '1' UNION ALL

SELECT CF2.CONTAINER_ID

FROM CONTEXTS CTXTS , CONTEXTS CTXTS2 , CONTEXT_FOLDERS CF2 ,