MybatisPlus条件构造器

allEq

allEq(Map< R, V> params)
allEq(Map< R, V> params, boolean null2IsNull)
allEq(boolean condition, Map< R, V> params, boolean null2IsNull)

• 全部eq或个别isNull

• params
  • key:数据库字段名
  • value:字段值
  • null2IsNull:true则在map的value为null时调用isNull，为false则忽略为null的value

allEq(BiPredicate< R, V> filter, Map< R, V> params)
allEq(BiPredicate< R, V> filter, Map< R, V> params, boolean null2IsNull)
allEq(boolean condition, BiPredicate< R, V> filter, Map< R, V> params, boolean
null2IsNull)

• filter:过滤函数 是否允许字段传入比对条件中

示例

@Test
public void testWrapper(){
Map< String,Object> params=new HashMap< >();
params.put("age",30);
params.put("name","Peyton Hogg");
params.put("password",null);
QueryWrapper< User> wrapper=new QueryWrapper< >();
//SELECT id,user_name,password,name,age,email FROM tb_user WHERE (password IS NULL AND name = ? AND age = ?)
//wrapper.allEq(params);
//SELECT id,user_name,password,name,age,email FROM tb_user WHERE (name = ? AND age = ?)
//wrapper.allEq(params,false);
//SELECT id,user_name,password,name,age,email FROM tb_user WHERE (age = ?)
wrapper.allEq((k,v)->(k.equals("age")),params);
List< User> users = userMapper.selectList(wrapper);
for (User user : users) {
System.out.println(user);
}
}

基本比较操作

• eq
  • 等于 =
• ne
  • 不等于 < >
• gt
  • 大于 >
• ge
  • 大于等于 >=
• lt
  • 小于<
• le
  • 小于等于< =
• between
  • BETWEEN 值1 AND 值2
• notBetween
  • NOTBETWEEN 值1AND 值2
• in
  • 字段 IN (values)
• notIn
  • 字段NOT IN(values)

示例

@Test
public void testWrapper(){
QueryWrapper< User> wrapper=new QueryWrapper< >();
//SELECT id,user_name,password,name,age,email FROM tb_user WHERE (age > ? AND id BETWEEN ? AND ?)
wrapper.gt("age",20).between("id",6L,9L);
List< User> users = userMapper.selectList(wrapper);
for (User user : users) {
System.out.println(user);
}
}

模糊查询

• like
  • LIKE ‘%值%’
• notLike
  • NOT LIKE ‘%值%’
• likeLeft
  • LIKE ‘%值’
• likeRight
  • LIKE ‘值%’

示例

@Test
public void testWrapper(){
QueryWrapper< User> wrapper=new QueryWrapper< >();
//Preparing: SELECT id,user_name,password,name,age,email FROM tb_user WHERE (name LIKE ?)
//Parameters: %n(String)
wrapper.likeLeft("name","n");
List< User> users = userMapper.selectList(wrapper);
for (User user : users) {
System.out.println(user);
}
}

排序

• orderBy
  • ORDER BY 字段
• orderByAsc 升序
  • ORDER BY 字段 ASC
• orderByDesc 降序
  • ORDER BY 字段 DESC

示例

@Test
public void testWrapper(){
QueryWrapper< User> wrapper=new QueryWrapper< >();
//SELECT id,user_name,password,name,age,email FROM tb_user ORDER BY age ASC
wrapper.orderByAsc("age");
List< User> users = userMapper.selectList(wrapper);
for (User user : users) {
System.out.println(user);
}
}

逻辑拼接

• or
  • 拼接OR
• and
  • AND嵌套

示例

@Test
public void testWrapper(){
QueryWrapper< User> wrapper=new QueryWrapper< >();
//SELECT id,user_name,password,name,age,email FROM tb_user WHERE (age = ? OR age = ?)
wrapper.eq("age",19).or().eq("age",24);
List< User> users = userMapper.selectList(wrapper);
for (User user : users) {
System.out.println(user);
}
}

select

可用于指定要查询的字段

示例

@Test
public void testWrapper(){
QueryWrapper< User> wrapper=new QueryWrapper< >();
//SELECT id,name,age FROM tb_user
wrapper.select("id","name","age");
List< User> users = userMapper.selectList(wrapper);
for (User user : users) {
System.out.println(user);
}
}

最后

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