sql-example.md

sql example

主键查询

SELECT * FROM user WHERE id = 1;

User user = userService.selectById(1);

字段与字段进行比较

SELECT * FROM user WHERE id = parent_id

userService.selectList(new SelectWrapper<User>()
                .eq(User::getId, User::getParentId)
        );

自定义更新

UPDATE user SET name = 'zhangsan', age = 3 WHERE id = 3;

userService.update(new UpdateWrapper<User>()
                .set(User::getName, "zhangsan")
                .set(User::getAge, 3)
                .eq(User::getId, 3)
        );

关联查询

SELECT id FROM user WHERE name LIKE '%zhangsan%' AND id IN (SELECT user_id from login_info WHERE last_login_date >= '2019-11-11')

userService.selectList(new SelectWrapper<User>()
                .select(User::getId)
                .like(User::getName, "zhangsan")
                .in(User::getAge, t->t.applySelectWrapper(LoginInfo.class).select(LoginInfo::getUserId).gt(User::getLastLoginDate, new Date))
        );