基于mybatis

目录

querywrapper排序的坑

大致可以总结成上面的两句话。

条件构造器querywrapper

我们再搞几个实例来深入理解下条件构造器querywrapper的用法：

案例一

查询姓李的，并且出生日期范围是1993-02-09到1994-04-09的员工

sql实现：

lect * from t_employee where date_format(bir实习周记第三周thday,'%y-%m-%d')>='1993-02-09' and date_format(birthday,'%y-%m-%d')<='1994-04-09' and name like '李%'

mp实现：

/** * 查询姓李的，并且出生日期范围是1993-02-09到1994-04-09的员工 * sql：lect * from t_employee where date_format(birthday,'%y-%m-%d')>='1993-02-09' and date_format(birthday,'%y-%m-%d')<='1994-04-09' and name like '李%' */@testpublic void lectbyquerywrapper3(){  querywrapper<employee> querywrapper=new querywrapper();  // querywrapper<employee> querywrapper2=wrapp感动中国观后感500ers.<employee>query();  que坚韧作文rywrapper.apply("date_format(birthday,'%y-%m-%d')>={0} and date_format(birthday,'%y-%m-%d')<={1}","1993-02-09","1994-04-09").likeright("name","李");  list<employee> employeelist = employeemapper.lectlist(querywrapper);  system.out.println(employeelist);}

案例二

查询姓李的或者邮箱不为空并且是女性的员工

sql实现：

lect * from t_employee where name like '李%' or (email is not null and gender ='女')

mp实现：

/*** 查询姓李的或者邮箱不为空并且是女性的员工* sql：lect * from t_employee where name like '李%' or (email is not nul我很爱你英文l and gender ='女')*/@testpublic void lectbyquerywrapper4(){ querywrapper<employee> querywrapper=new querywrapper(); // querywrapper<employee> querywrapper2=wrappers.<employee>query(); querywrapper.likeright("name","李").or(wq->wq.isnotnull("email").eq("gender","女")); list<employee> employeelist = employeemapper.lectlist(querywrapper); system.out.println(employeelist);}

案例三

查询姓李的并且邮箱不为空或者是女性的员工

sql实现：

lect * from t_employee where name like '李%' and (email is not null or gender ='女')

mp实现：

/*** 查询姓李的并且邮箱不为空或者是女性的员工* sql：lect * from t_employee where name like '李%' and (email is not null or gender ='女')*/@testpublic void lectbyquerywrapper5(){ querywrapper<employee> querywrapper=new querywrapper(); // querywrapper<employee> querywrapper2=wrappers.<employee>query(); querywrapper.likeright("name","李").and(wq->wq.isnotnull("email").or().eq("gender","女")); list<employee> employeelist = employeemapper.lectlist(querywrapper); system.out.println(employeelist);}

案例四

查询属于编号1,2,3部门的并且薪水小于等于3500的员工 根据年龄从大到小排序显示

sql实现：

lect * from t_employee where salary<=3500 and departmentid in (1,2,3) order by birthday asc

mp实现：

/*** 查询属于编号1,2,3部门的并且薪水小于等于3500的员工 根据年龄从大到小排序显示* sql：lect * from t_employee where salary<=3500 and departmentid in (1,2,3) order by birthday asc*/@testpublic void lectbyquerywrapper6(){ querywrapper<employee> querywrapper=new querywrapper(); // querywrapper<employee> querywrapper2=wrappers.<employee>query(); querywrapper.liker小燕子歌词ight("name","李").and(wq->wq.isnotnull("email").or().eq("gender","女")); list<employee> employeelist = employeemapper.lectlist(querywrapper); system.out.println(employeelist);}

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