【java】mybatis-plus lambda表达式符号总结

1.函数名及用法

//查询学生
QueryWrapper<Student> queryWrapper = new QueryWrapper();

函数	说明	举例
eq	equals等于(=)	queryWrapper.lambda().eq(Student::getName,“老王”);
ne	not equals不等于(<>)	queryWrapper.lambda().ne(Student::getName,“老王”);
gt	greater than大于(>)	queryWrapper.lambda().gt(Student::getAge,26);
ge	greater or equals大于等于(>=)	queryWrapper.lambda().ge(Student::getAge,26);
lt	less than小于(<)	queryWrapper.lambda().lt(Student::getAge,26);
le	less or equals小于等于(<=)	queryWrapper.lambda().le(Student::getAge,26);
between	between a and b	queryWrapper.lambda().between(Student::getAge,26,30);
notBetween	not between a and b	queryWrapper.lambda().notBetween(Student::getAge,26,30);
like	like ‘%值%’	queryWrapper.lambda().like(Student::getName,“老王”);
notLike	not like ‘%值%’	queryWrapper.lambda().notLike(Student::getName,“老王”);
likeLeft	like ‘%值’	queryWrapper.lambda().likeLeft(Student::getName,“老王”);
likeRight	like ‘值%’	queryWrapper.lambda().likeRight(Student::getName,“老王”);
isNull	字段 is null	queryWrapper.lambda().isNull(Student::getName);
isNotNull	字段 is not null	queryWrapper.lambda().isNotNull(Student::getName);
in	字段 in (a,b,c)	queryWrapper.lambda().in(Student::getId, idList);//注意判断idList不为空
notIn	字段 not in (a,b,c)	queryWrapper.lambda().notIn(Student::getId, idList);//注意判断idList不为空
inSql	字段 in (sql语句)	queryWrapper.lambda().inSql(Student::getId,“select id from student where is_deleted = 0”);//id in (select id from student where is_deleted = 0);
notInSql	字段 not in (sql语句)	queryWrapper.lambda().notInSql(Student::getId,“select id from student where is_deleted = 0”);//id not in (select id from student where is_deleted = 0);
groupBy	group by 字段a,字段b	queryWrapper.lambda().groupBy(Student::getId,Student::getName);
orderBy	order by 字段a,字段b	queryWrapper.lambda().orderBy(Student::getId,Student::getName);
orderByAsc	order by 字段a,字段b asc	queryWrapper.lambda().orderByAsc(Student::getId,Student::getName);
orderByDesc	order by 字段a,字段b desc	queryWrapper.lambda().orderByDesc(Student::getId,Student::getName);
having	having (sql语句)	queryWrapper.lambda().having(“sum(age) > {0}”, 122);//having sum(age) > 22;
or	or拼接	queryWrapper.lambda().eq(Student::getName,“老王”).or().eq(Student::getName,“老李”);// and name ='老王’ or name = ‘老李’;
and	and嵌套	queryWrapper.lambda().and(obj ->obj.eq(TemplateEntity::getName, “老王”).or().like(TemplateEntity::getName, ‘王’));//and (name = ‘老王’ or name like ‘%王%’);
apply	拼接sql	queryWrapper.lambda().apply(" and date_format(update_time, ‘%Y-%m-%d’) ={0}",“2021-10-16”);//and date_format(update_time, ‘%Y-%m-%d’) = ‘2021-10-16’; 直接传参会有sql注入风险
last	无视优化规则直接拼接到sql最后	queryWrapper.lambda().last(" limit 1,10");// limit 1,10; 只能调用一次,多次调用以最后一次为准，有sql注入的风险,请谨慎使用
exists	拼接exists语句	queryWrapper.lambda().exists(" select id from student where name = '老王‘’");// exists (select id from student where name = ‘老王’);
notExists	拼接not exists语句	queryWrapper.lambda().notExists(" select id from student where name = '老王‘’");// not exists (select id from student where name = ‘老王’);
nested	正常嵌套不带AND或者OR	queryWrapper.lambda().nested(obj -> obj.eq(TemplateEntity::getName, “老王”).ne(TemplateEntity::getAge, 26));//and name = ‘老王’ and age != 26;