selectSub

子查询

selectSub 1.4.5+

class MpJoinTest {
    @Resource
    private UserMapper userMapper;

    @Test
    void sub() {
        MPJLambdaWrapper<User> wrapper = JoinWrappers.lambda(User.class)
                .selectSub(User.class, w -> w.select(User::getId)
                        .eq(User::getId, User::getId)
                        .last("limit 1"), User::getId)
                .leftJoin(Address.class, Address::getUserId, User::getId)
                .le(User::getId, 100);
        wrapper.list();
    }
}

对应log

SELECT 
    (SELECT st.id FROM `user` st WHERE (st.id = t.id) limit 1 ) AS id
FROM `user` t LEFT JOIN address t1
ON (t1.user_id = t.id)
WHERE t1.del= false AND (t.id <= ?)

提示:

st 是默认的子查询中的主表别名