技术宅，fat-man

摘要： 从DBA那问来的，备份现有数据库表：create table B select * from A ;删除，重建数据库主键alter table book_order drop primary key; alter table book_order add primary key(bookid,platform,stat_date);根据小时分组数据select date_format(inserttime,'%Y-%m-%d %H'),count(userid), count(distinct userid) from pppay_order_alipay where stat 阅读全文