top是sql server的用法 SELECT t3.* FROM(SELECT top 2 t2.* FROM (SELECT top 3 NAME,SUBJECT,score,stuid FROM stuscore WHERE SUBJECT = '数学'ORDER BY score DESC) t2 ORDER BY t2.score) t3 ORDER BY t3.scor
本章节主要实现两个一对一关联表的查询,例如表PERSON 表PHONE 上述两个表一对一关联,一个人只能有一部手机。例如查询id为1的那个人的手机价格,sql 查询语句为: SELECT * FROM person p1, phone p2 WHERE p1.phone_brand = p2.phone_brand AND p1.id=1 下面通过Mybaits实现此一对一关联表查
部分数据 1distinct去重 select distinct job from tb_emp;select * from tb_emp where id in (1,2,3);select * from tb_emp where id between 1 and 5;select * from tb_emp where name like '__'; #下划线匹配单个字符, %匹
方法一:select * from 表名 where time between to_date('2012-06-18 00:00:00','yyyy-mm-dd hh24:mi:ss') and to_date('2012-06-18 23:59:59','yyyy-mm-dd hh24:mi:ss');方法二:select * from 表名 where to_char(indate,'yy
微信小程序多个请求防止并发处理。 wx.request({url: '你的地址',data: {//携带的参数},success: function (res) {//成功 do something},fail: function () { //失败 do something},complete: function () {//不论成功还是失败都会到这里面。第二个请求放在第一个请求的compl