基于mybatis-plus QueryWrapper 排序的坑

更新時(shí)間：2022年01月30日 10:06:15 作者：summer_wu

這篇文章主要介紹了mybatis-plus QueryWrapper 排序的坑，具有很好的參考價(jià)值，希望對(duì)大家有所幫助。如有錯(cuò)誤或未考慮完全的地方，望不吝賜教

QueryWrapper排序的坑

大致可以總結(jié)成上面的兩句話。

條件構(gòu)造器QueryWrapper

我們?cè)俑銕讉€(gè)實(shí)例來(lái)深入理解下條件構(gòu)造器QueryWrapper的用法：

案例一

查詢姓李的，并且出生日期范圍是1993-02-09到1994-04-09的員工

sql實(shí)現(xiàn)：

SELECT * 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%'

mp實(shí)現(xiàn)：

/**
 * 查詢姓李的，并且出生日期范圍是1993-02-09到1994-04-09的員工
 * sql：SELECT * 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%'
 */
@Test
public void selectByQueryWrapper3(){
  QueryWrapper<Employee> queryWrapper=new QueryWrapper();
  // QueryWrapper<Employee> queryWrapper2=Wrappers.<Employee>query();
  queryWrapper.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.selectList(queryWrapper);
  System.out.println(employeeList);
}

案例二

查詢姓李的或者郵箱不為空并且是女性的員工

sql實(shí)現(xiàn)：

SELECT * FROM t_employee WHERE NAME LIKE '李%' OR (email IS NOT NULL AND gender ='女')

mp實(shí)現(xiàn)：

/**
?* 查詢姓李的或者郵箱不為空并且是女性的員工
?* sql：SELECT * FROM t_employee WHERE NAME LIKE '李%' OR (email IS NOT NULL AND gender ='女')
?*/
@Test
public void selectByQueryWrapper4(){
? 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.selectList(queryWrapper);
? System.out.println(employeeList);
}

案例三

查詢姓李的并且郵箱不為空或者是女性的員工

sql實(shí)現(xiàn)：

SELECT * FROM t_employee WHERE NAME LIKE '李%' AND (email IS NOT NULL OR gender ='女')

mp實(shí)現(xiàn)：

/**
?* 查詢姓李的并且郵箱不為空或者是女性的員工
?* sql：SELECT * FROM t_employee WHERE NAME LIKE '李%' AND (email IS NOT NULL OR gender ='女')
?*/
@Test
public void selectByQueryWrapper5(){
? 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.selectList(queryWrapper);
? System.out.println(employeeList);
}

案例四

查詢屬于編號(hào)1,2,3部門的并且薪水小于等于3500的員工根據(jù)年齡從大到小排序顯示

sql實(shí)現(xiàn)：

SELECT * FROM t_employee WHERE salary<=3500 AND departmentId IN (1,2,3) ORDER BY birthday ASC

mp實(shí)現(xiàn)：

/**
?* 查詢屬于編號(hào)1,2,3部門的并且薪水小于等于3500的員工 根據(jù)年齡從大到小排序顯示
?* sql：SELECT * FROM t_employee WHERE salary<=3500 AND departmentId IN (1,2,3) ORDER BY birthday ASC
?*/
@Test
public void selectByQueryWrapper6(){
? 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.selectList(queryWrapper);
? System.out.println(employeeList);
}

以上為個(gè)人經(jīng)驗(yàn)，希望能給大家一個(gè)參考，也希望大家多多支持腳本之家。

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