postgreSQL 17.01: string split function

SELECT 'S0001' AS STU,
  unnest(string_to_array('G,E,O,V,I,N,D,U,B,,A,B,C,D,A,B,D,B,C,C,B,A,B,D,A,C,D,A,B,D,A,D,C,B,D,B,D,B,A,C,D,A,C,D,A,A,C,B,A,D', ',')) AS parts;
  
delete from Answer where AnswerSudentId='S0001';
drop table IF EXISTS TempSubString;
CREATE TABLE TempSubString(
id SERIAL,
studentid varchar(5),
subname VARCHAR(150),
PRIMARY KEY(id) 
);
 
insert into TempSubString(studentid,subname) 
SELECT 'S0001' AS STU,unnest(string_to_array('A,,B,C,D,A,B,D,B,,A,B,C,D,A,B,D,B,C,C,B,A,B,D,A,C,D,A,B,D,A,D,C,B,D,B,D,B,A,C,D,A,C,D,A,A,C,B,A,D', ',')) AS parts;
--  每题的得分 考虑，是否存在记录，存在删除，不存在，直接添加 Geovin Du
--  delete from  Answer where AnswerSudentId=@studentid;
insert into Answer(AnswerSudentId,AnswerQuestionId,AnswerStudentResult,AnswerScore) select studentid,id,subname,f_GetAnswerScore(id,subname) as score from TempSubString ; 
 
SELECT * FROM Answer;