Oracle Gets Split items

Oracle to a comma-separated string that can be converted into a conditional statement of the number of characters in a column
string coming from the front desk: '589,321' 

SELECT
*
FROM TAB_A T1 
WHERE  T1.CODE  IN (

SELECT REGEXP_SUBSTR('589,321','[^,]+', 1, LEVEL) FROM DUAL

CONNECT BY REGEXP_SUBSTR('SMITH,ALLEN,WARD,JONES', '[^,]+', 1, LEVEL) IS NOT NULL

)