MySQL note.md

• 总天数 select to_days('2015-1-18')
• 当前时间与特定时间所差周数的实现

  declare i int;
  set i =  timestampdiff(week,date(date_add(p_time,interval 8-dayofweek(p_time) day)),date(date_add(now(),interval 8-dayofweek(now()) day)));
  return  if(i<0,abs(i),i+1) ;

• limit后只能跟常量
• count() 返回hibernate是BigInteger
• hibernate 返回值不add scale,直接返回Object[] 时，sql里不能设置别名 如select text.text as name
• update table set 。。 where id=(select * from (select max(id) from table) as A)必须再次select下
• SET GLOBAL event_scheduler = ON; 或者在mysql.ini下添加event_scheduler=1
• update可以用order by limit 1
• alter table users AUTO_INCREMENT=123456
• cursor 一定要在not found 时设置标记 然后leave loop。否则死循环！！！！2货