Question

我需要找到上周的顶级申请人，但我的SQL查询中出现错误。

  var queryString = "select id, created_at, user_id, count(id) as cnt from "+
      "applications where id in (select id from applications where "+
      "created_at > current_date - interval '1 week') group by user_id";

data.sql

insert into listings (id, created_at, created_by, name, description) values
    (1, '2015-01-15 11:00', 1, 'Join us conquering the world!', 'This is your best chance to be on the right side of the equation...')
;

insert into listings (id, created_at, created_by, name, description) values
    (1, '2015-01-15 11:00', 1, 'Join us conquering the world!', 'This is your best chance to be on the right side of the equation...')
;

insert into listings (id, created_at, created_by, name, description) values
    (2, '2017-01-29 11:00', 1, 'Join us conquering the world!', 'Holla ho')
;

insert into listings (id, created_at, created_by, name, description) values
    (3, '2017-01-15 11:00', 1, 'Join us conquering the world!', 'Hey ya')
;

insert into applications (created_at, user_id, listing_id, cover_letter) values
    ('2017-02-23 12:00', 2, 1, 'Hello, ...')
;

INSERT INTO APPLICATIONS (CREATED_AT, USER_ID, LISTING_ID, COVER_LETTER) VALUES
    ('2017-02-24 12:00', 2, 2, 'HELLO, ...')
;

INSERT INTO APPLICATIONS (CREATED_AT, USER_ID, LISTING_ID, COVER_LETTER) VALUES
    ('2017-02-22 12:00', 2, 2, 'HELLO, ...')
;

INSERT INTO APPLICATIONS (CREATED_AT, USER_ID, LISTING_ID, COVER_LETTER) VALUES
    ('2017-02-25 12:00', 3, 1, 'HELLO, ...')
;

这是错误：

column "applications.id" must appear in the GROUP BY clause or be used in an aggregate function

我做错了什么？

所以，基本上我希望看到用户2用3个应用，用户ID为3，用1个应用。

Answer 1

您可能打算进行此查询：

select user_id, count(id) as cnt
from applications
where id in (select id
             from applications 
             where created_at > current_date - interval '1 week'
            )
group by user_id;

请注意从select。

中删除的列

如果我们假设id实际上是唯一的，您可以这样做：

select user_id, count(id) as cnt
from applications
group by user_id
having max(created_at) > current_date - interval '1 week';

SQL聚合列问题

1 个答案: