将 2 个 SQL SELECT 结果加入一个查询

Question

我想知道是否有办法将两个或多个结果集合并为一个。 我有以下两个查询 第一个查询：

SELECT
  CONCAT(day(db.prod_id.created_on),"-",month(db.prod_id.created_on),"-",year(db.prod_id.created_on)) as day_month_year,
  db.country.country ,
  count(concat(day(db.prod_id.created_on),"-",month(db.prod_id.created_on),"-",year(db.prod_id.created_on))) as count ,
  COUNT(DISTINCT db.prod_id.email) AS MAIL
from db.prod_id
left join db.country on db.prod_id.branch_id = db.country.id
where  db.prod_id.created_on > '2020-11-17'  and (db.country.type = 1 or db.country.type = 2)
group by
  concat(day(db.prod_id.created_on),"-",month(db.prod_id.created_on),"-",year(db.prod_id.created_on)),
  db.country.country
order by db.prod_id.created_on

第二个查询：

select
  CONCAT(day(db.prod_id.created_on),"-",month(db.prod_id.created_on),"-",year(db.prod_id.created_on)) as day_month_year,
  db.country.country,
  count(CONCAT(day(db.prod_id.created_on),"-",month(db.prod_id.created_on),"-",year(db.prod_id.created_on))) as count_BUY
from db.prod_id
left join db.prod_evaluations on db.prod_id.id = db.prod_evaluations.id
left join db.country on db.prod_id.branch_id = db.country.id
left join (Select prod_properties.prod_id, prod_properties.value From prod_properties Where prod_properties.property_id = 5) as db3 on db3.prod_id = db.prod_id.id
where db.prod_id.created_on > '2020-11-17'
and db3.value  = 'online-buy' and db.prod_id.status_id <> 25
group by
  concat(day(db.prod_id.created_on),"-",month(db.prod_id.created_on),"-",year(db.prod_id.created_on)),
  db.country.country
order by db.prod_id.created_on

第一个查询给出以下结果：

+------------+---------+--------+------+ |天 |国家 |计数 |邮件 | +------------+---------+--------+------+ | 17-11-2020 |资讯科技 | 200 | 100 | | 17-11-2020 |美国 | 250 | 100 | | 18-11-2020 |资讯科技 | 350 | 300 | | 18-11-2020 |美国 | 200 | 100 | +------------+---------+--------+------+

第二个查询给出：

+------------+---------+------------+ |天 |国家 |计数_购买 | +------------+---------+------------+ | 17-11-2020 |资讯科技 | 50 | | 17-11-2020 |美国 | 70 | | 18-11-2020 |资讯科技 | 200 | | 18-11-2020 |美国 | 50 | +------------+---------+------------+

现在我想将这两个结果合并为一个：

+------------+---------+--------+------+----------- + |天 |国家 |计数 |邮件 |计数_购买 | +------------+---------+--------+------+----------- + | 17-11-2020 |资讯科技 | 200 | 100 | 50 | | 17-11-2020 |美国 | 250 | 100 | 70 | | 18-11-2020 |资讯科技 | 350 | 300 | 200 | | 18-11-2020 |美国 | 200 | 100 | 50 | +------------+---------+--------+------+----------- +

如何执行此查询？ 我正在使用 mysql 谢谢

Answer 1

简单的方法：你可以加入查询。

select *
from ( <your first query here> ) first_query
join ( <your second query here> ) second_query using (day_month_year, country)
order by day_month_year, country;

这是一个内部连接。当然，您也可以外连接。不过，MySQL 不支持 full 外连接。如果你想这样做，你必须查看如何在 MySQL 中模拟完全外部连接。

困难的方式 ;-) 合并查询。

如果我没记错的话，你的两个查询可以简化为

select
  date(created_on),
  branch_id as country,
  count(*) as count_products,
  count(distinct p.email) as count_emails
from db.prod_id
where created_on >= date '2020-11-17'
and branch_id  in (select country from db.country where type in (1, 2))
group by date(created_on), branch_id
order by date(created_on), branch_id;

和

select
  date(created_on),
  branch_id as country,
  count(*) as count_buy
from db.prod_id
where created_on >= date '2020-11-17'
and status_id <> 25
and prod_id in (select prod_id from prod_properties where property_id = 5 and status_id <> 25)
group by date(created_on), branch_id
order by date(created_on), branch_id;

两者结合应该是

select
  date(created_on),
  branch_id as country,
  sum(branch_id in (select country from db.country where type in (1, 2)) as count_products,
  count(distinct case when branch_id  in (select country from db.country where type in (1, 2) then p.email end) as count_emails,
  sum(status_id <> 25 and prod_id in (select prod_id from prod_properties where property_id = 5 and status_id <> 25)) as count_buy
from db.prod_id
where created_on >= date '2020-11-17'
group by date(created_on), branch_id
order by date(created_on), branch_id;

您会看到，查询的共同条件保留在 where 子句中，而其他条件则放在聚合函数中。

sum(boolean) 是 sum(case when boolean then 1 else 0 end) 的缩写，即计算 MySQL 中满足条件的行数。