sql 编辑

1.查询前几条数据用：limit
eg:SELECT * FROM item ORDER BY price DESC LIMIT 0,5(查询价格最贵的前五条美容项目记录)

2.升序（asc），降序(desc)

3.防止sql注入
// 定义hql语句
String hql = "from MemberEntity WHERE no LIKE ? OR name LIKE ? OR realname LIKE ?";
Object[] paramValues = new Object[3];
paramValues[0]=condition+"%";
paramValues[1]="%"+condition+"%";
paramValues[2]="%"+condition+"%";
List<MemberEntity> memberlist = systemService.findHql(hql, paramValues);

4.日期加一（interval）
// 下月生日的会员
month(birthday)=month(date_add(CURDATE(),interval 1 MONTH));

5.日期格式年月日的转化（2015-12-07）
DATE_FORMAT(handle_time,'%Y-%m-%d')

6.

/* 查询出会员信息表中会员编号相同的人*/

select * from member a where exists (select count(*),`no` from member b where a.`no` = b.`no` having count(*) > 1);