JSON Concat in ORACLE

Input table :

Create table TEST_TBL(Item varchar2(100),loc varchar2(100), ATTRIBUTE BLOB);

INSERT INTO TEST_TBL('ABC','XYZ',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST","attrValue":"REC","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL('ABC','XYZ',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST1","attrValue":"REC1","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL('ABC','XYZ',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST2","attrValue":"REC2","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL('CDE','WER',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST5","attrValue":"REC5","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL('CDE','WER',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST6","attrValue":"REC6","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
COMMIT;

Desired output would be if item and loc combination is same then Attribute will be concatenated like below:

Output:

INSERT INTO TEST_TBL('ABC','XYZ',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST","attrValue":"REC","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}],            [{"attrName":"TEST1","attrValue":"REC1","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}],            [{"attrName":"TEST2","attrValue":"REC2","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL('CDE','WER',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST5","attrValue":"REC5","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}],             [{"attrName":"TEST6","attrValue":"REC6","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));

If you want to display the merged rows then:

SELECT t.item, t.loc,
       JSON_ARRAYAGG(j.attr FORMAT JSON) AS attrs
FROM   test_tbl t
       CROSS APPLY JSON_TABLE(
         t.attribute,
         '$[*]'
         COLUMNS(
           attr CLOB FORMAT JSON PATH '$'
         )
       ) j
GROUP BY item, loc

Which, for the sample data:

Create table TEST_TBL(
  Item varchar2(100),
  loc varchar2(100),
  ATTRIBUTE BLOB CHECK (attribute IS JSON)
);

INSERT INTO TEST_TBL (item, loc, attribute) VALUES ('ABC','XYZ',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST","attrValue":"REC","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL (item, loc, attribute) VALUES ('ABC','XYZ',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST1","attrValue":"REC1","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL (item, loc, attribute) VALUES ('ABC','XYZ',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST2","attrValue":"REC2","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL (item, loc, attribute) VALUES ('CDE','WER',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST5","attrValue":"REC5","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
INSERT INTO TEST_TBL (item, loc, attribute) VALUES ('CDE','WER',UTL_RAW.CAST_TO_RAW('[{"attribute":[{"attrName":"TEST6","attrValue":"REC6","attrOperator":"EQUAL","attrOverrideParam":"Priority","attrOverrideValue":0}]}]'));
COMMIT;

Outputs:

fiddle