See this answer.
Use LIKE
:
INNER JOIN student_unit_attempt sua
on sua.person_id=sei.person_id
AND sua.course_cd=sei.course_cd
AND sua.unit_cd=sei.unit_cd
AND ','||l_unit_attempt_status||',' LIKE '%,'''||sua.unit_attempt_status||''',%'
Or pass in a collection:
CREATE TYPE status_list IS TABLE OF varchar2(20);
DECLARE
l_unit_attempt_status status_list := status_list( 'COMPLETED','DISCONTIN','DUPLICATE','ENROLLED','INVALID','UNCONFIRM' );
BEGIN
SELECT <your_column_list>
INTO <variables>
FROM table_name sei
INNER JOIN student_unit_attempt sua
on sua.person_id=sei.person_id
AND sua.course_cd=sei.course_cd
AND sua.unit_cd=sei.unit_cd
AND sua.unit_attempt_status MEMBER OF l_unit_attempt_status;
END;
/
Or split the list:
INNER JOIN student_unit_attempt sua
on sua.person_id=sei.person_id
AND sua.course_cd=sei.course_cd
AND sua.unit_cd=sei.unit_cd
AND sua.unit_attempt_status in ( SELECT COLUMN_VALUE
FROM XMLTABLE( l_unit_attempt_status ) )