找到办法了
CREATE TABLE a_test (
ID INT PRIMARY KEY,
Src1 VARCHAR(100)
);

INSERT INTO a_test (ID, Src1) VALUES
(1, 'A,B,C'),
(2, 'D,E,F');

select ID
,Src1
, column_value AS FileName
from (
SELECT id,
Src1,
XMLPARSE(DOCUMENT '<root><v>' || REPLACE(Src1, ',', '</v><v>') || '</v></root>') AS file_xml
FROM a_test

) as b
OUTER APPLY XMLTable('/root/v' PASSING file_xml COLUMNS column_value VARCHAR PATH '.' ) AS x
where column_value is not NULL