题解 | #修复串列了的记录#
修复串列了的记录
https://www.nowcoder.com/practice/a5475ed3b5ab4de58e2ea426b4b2db76
select exam_id , left(tag, instr(tag, ',') - 1) , substring_index(substring_index(tag, ',', -2), ',', 1) difficulty , substring_index(tag, ',', -1) as duration from examination_info where duration = 0