QueryWrapper常用方法列表
函数 | 意义 | 举例 |
---|---|---|
eq | 等于(=) | queryWrapper.eq(“user_name”, “张三”); //user_name=“张三” |
ne | 不等于(<>) | queryWrapper.ne(“user_name”, “张三”); //user_name<>“张三” |
gt | 大于(>) | queryWrapper.gt(“level”, 1); //level>1 |
ge | 大于等于(>=) | queryWrapper.ge(“level”, 1); //level>=1 |
lt | 小于(<) | queryWrapper.lt(“level”, 1); //level<1 |
le | 小于等于(<=) | queryWrapper.le(“level”, 1); //level<=1 |
between | 值1和值2之间 | queryWrapper.between(“level”, 1,10); //level>=1 and level <=10 |
notBetween | 不在值1和值2之间 | queryWrapper.notBetween(“level”, 1,10);//level<1 or level >10 |
like | 模糊匹配 like %值% | queryWrapper.like(“user_name”, “张三”); //user_name like “%张三%” |
not like | 不模糊匹配 not like %值% | queryWrapper.notLike(“user_name”, “张三”); //user_name not like “%张三%” |
likeLeft | 左模糊匹配 like %值 | queryWrapper.likeLeft(“user_name”, “张三”); //user_name like “%张三” |
likeRight | 右模糊匹配 like 值% | queryWrapper.likeRight(“user_name”, “张三”); //user_name like “张三%” |
isNull | 字段 为空 | queryWrapper.isNull(“user_name”);//user_name is null |
isNotNull | 字段 不为空 | queryWrapper.isNotNull(“user_name”);//user_name is not null |
in | 字段 in (v0,v1,…) | queryWrapper.in(“user_name”, {“张三”,“李四”,“王五”}); // user_name in (“张三”,“李四”,“王五”) |
notIn | 字段 not in (v0,vl,…) | queryWrapper.notIn(“user_name”, {“张三”,“李四”,“王五”}); // user_name not in (“张三”,“李四”,“王五”) |
inSql | 字段 in ( sql语句) | queryWrapper.in(“user_name”, (select name from student where age< 23)); // user_name in (select name from student where age< 23) |
notInSql | 字段 not in ( sql语句) | queryWrapper.notIn(“user_name”, (select name from student where age< 23)); // user_name not in (select name from student where age< 23) |
groupBy | 分组:GROUP BY 字段 | queryWrapper.groupBy(“user_name”);//group by user_name |
orderByAsc | 排序:ORDER BY 字段 ASC | queryWrapper.orderByAsc(“createTime”);//order by createTime asc |
orderByDesc | 排序:ORDER BY 字段 DESC | queryWrapper.orderByDesc(“createTime”);//order by createTime desc |
orderBy | 排序:ORDER BY 字段 | queryWrapper.orderBy(true, true, “createTime”);//order by createTime asc |
or | 拼接 OR | 说明:主动调用or表示紧接着下一个方法不是用and连接!(不调用or则默认为使用and连接);queryWrapper.eq(“id”, “1”).or().eq(“user_name”, “张三”); //id = 1 or name =‘张三’ |
and | 拼接 AND | queryWrapper.eq(“id”, “1”).and(i->i.eq(“user_name”, “张三”)); //id = 1 and name =‘张三’ |
apply | 拼接 sql | 说明: 该方法可用于数据库函数动态入参的params;queryWrapper.eq(“id”, user.getId()).apply(“date_format(‘createTime’,‘%Y-%m-%d’) = {0}”,“2023-07-25”);//date_format(‘createTime’,'%Y-%m-%d) =‘2023-07-25’") |
last | 无视优化规则直接拼接到 sql 的最后 | 说明:只能调用一次,多次调用以最后一次为准 有sq1注入的风险,请谨慎使用queryWrapper.last(" limit 1");// limit 1 |
exists | 拼接 EXISTS(sql语句) | queryWrapper.exists(“SELECT id FROM Student WHERE User.id = Student.userId”);// exists (“SELECT id FROM Student WHERE User.id = Student.userId”) |
notExists | 拼接 NOT EXISTS (sg1语句) | queryWrapper.notExists(“SELECT id FROM Student WHERE User.id = Student.userId”);// not exists (“SELECT id FROM Student WHERE User.id = Student.userId”) |
nested | 正常嵌套不带 AND或者 OR | queryWrapper.nested(i->i.eq(“id”,“1”).eq(“user_name”,“张三”));// id = 1 and user_name=“张三” |
having | having ( sql语句) | queryWrapper.having(“sum(age) > {0}”,10);//having sum(age) > 10; |
常用的函数有eq等于
,like模糊查询
,between两值之间
如果是单创建QueryWrapper对象,最后查询想放在集合内的,可以调用mapper层继承的baseMapper内的17个操作方法之一selectList
返回一个集合对象
public 类型 方法名(){
创建一个wrapper对象
给这个对象加上查询条件,在条件里写对字段的限制,就是上面的常用方法
返回basemapper里的查询方法selectList用这个查询方法查询wrapper对象
}