摘要: SELECT COUNT(DISTINCT column(s)) FROM table // 先group by,然后select,然后order byselect xxx from xxx where xxx and xxxx group by homework_id order by num d 阅读全文
posted @ 2020-08-03 10:16 泥土里的绽放 阅读(56) 评论(0) 推荐(0) 编辑