Mybatis-Plus select不列出全部字段的方法
mybatis-plus select查询语句默认是查全部字段，有两种方法可以指定要查询的字段
CREATE TABLE `user` ( `id` bigint(20) NOT NULL COMMENT '主键', `name` varchar(30) DEFAULT NULL COMMENT '姓名', `age` int(11) DEFAULT NULL COMMENT '年龄', `email` varchar(50) DEFAULT NULL COMMENT '邮箱', `manager_id` bigint(20) DEFAULT NULL COMMENT '直属上级id', `create_time` datetime DEFAULT NULL COMMENT '创建时间', PRIMARY KEY (`id`), KEY `manager_fk` (`manager_id`), CONSTRAINT `manager_fk` FOREIGN KEY (`manager_id`) REFERENCES `user` (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
1、user表只需要查询出name和age两个字段的数据，可以使用queryWrapper的select()方法指定要查询的字段
@Test
public void selectByWrapper10() {
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.select("name", "age").like("name", "雨");
List<User> users = userMapper.selectList(queryWrapper);
users.forEach(System.out::println);
}
日志输出sql：
DEBUG==> Preparing: SELECT name,age FROM user WHERE name LIKE ?
DEBUG==> Parameters: %雨%(String)
TRACE<== Columns: name, age
TRACE<== Row: 张雨琪, 31
TRACE<== Row: 刘红雨, 31
DEBUG<== Total: 2
2、user表要查询出除manager_id和create_time外其它所有字段的数据，同样也是使用queryWrapper的select()方法
@Test
public void selectByWrapper11() {
QueryWrapper<User> queryWrapper = new QueryWrapper<>();
queryWrapper.select(User.class, info -> !info.getColumn().equals("manager_id")
&& !info.getColumn().equals("create_time"));
List<User> users = userMapper.selectList(queryWrapper);
users.forEach(System.out::println);
}
日志输出sql：
DEBUG==> Preparing: SELECT id,name,age,email FROM user
DEBUG==> Parameters:
TRACE<== Columns: id, name, age, email
TRACE<== Row: 1087982257332887553, 大boss, 40, boss@baomidou.com
TRACE<== Row: 1088248166370832385, 王天风, 25, wtf@baomidou.com
TRACE<== Row: 1088250446457389058, 李艺伟, 28, lyw@baomidou.com
TRACE<== Row: 1094590409767661570, 张雨琪, 31, zjq@baomidou.com
TRACE<== Row: 1094592041087729666, 刘红雨, 31, lhm@baomidou.com
DEBUG<== Total: 5
