WITH t AS ( SELECT '0,1,2' v FROM dual UNION ALL SELECT ',1,2,3' FROM dual UNION ALL SELECT '4,5,6,' FROM dual UNION ALL SELECT ',7,8,9,' FROM dual ) SELECT v , ',' || TRIM(BOTH ',' FROM v) || ',' v1 -- 1. 앞뒤 컴마 제거 후 일괄 붙이기 , REPLACE(',' || v || ',', ',,', ',') v2 -- 2. 일단 컴마 붙이고 컴마 두개를 Replace , DECODE(SUBSTR(v, 1, 1), ',', '', ',') || v || DECODE(SUBSTR(v, -1, 1), ',', '', ',') v3 -- 3. 컴마 있는지 확인하여 붙이기 FROM t ;