1.使用分割符號

 select regexp_substr('A_B_C', '[^_]+', 1, 2) FROM DUAL

2.練習2

SELECT SUBSTR(path_string,   
              INSTR(path_string, '\', -1, 2) + 1,   
              INSTR(path_string, '\', -1) - INSTR(path_string, '\', -1, 2) - 1) AS extracted_string  
FROM (SELECT 'D:\SKY Image\A0-BOTC8-20-128\BOTC8-20-128_X-ray1003_2024042320\22_GPC__233_1_Pass(正常).jpg' AS path_string FROM dual) t;