Mysql 如何获得相关表中字段的计数和？_Mysql_Join_Count_Sum

Mysql 如何获得相关表中字段的计数和？

mysql join

Mysql 如何获得相关表中字段的计数和？,mysql,join,count,sum,Mysql,Join,Count,Sum,我有三张桌子：分区表： +--------------------------+---------------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------------------+---------------------+-----

我有三张桌子：

分区表：

+--------------------------+---------------------+------+-----+---------+----------------+
| Field                    | Type                | Null | Key | Default | Extra          |
+--------------------------+---------------------+------+-----+---------+----------------+
| id                       | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| location_id              | bigint(20) unsigned | NO   | MUL | NULL    |                |
| impressions_count        | bigint(20) unsigned | YES  |     | 0       |                |
| created                  | datetime            | YES  |     | NULL    |                |
| modified                 | datetime            | YES  |     | NULL    |                |
+--------------------------+---------------------+------+-----+---------+----------------+

+----------------+---------------------+------+-----+---------+----------------+
| Field          | Type                | Null | Key | Default | Extra          |
+----------------+---------------------+------+-----+---------+----------------+
| id             | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| retailer_id    | bigint(20) unsigned | NO   | MUL | NULL    |                |
| zones_count    | int(10) unsigned    | YES  |     | 0       |                |
| contacts_count | int(10) unsigned    | YES  |     | 0       |                |
| created        | datetime            | YES  |     | NULL    |                |
| modified       | datetime            | YES  |     | NULL    |                |
+----------------+---------------------+------+-----+---------+----------------+

+---------------------+---------------------+------+-----+---------+----------------+
| Field               | Type                | Null | Key | Default | Extra          |
+---------------------+---------------------+------+-----+---------+----------------+
| id                  | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| account_rep_id      | bigint(20) unsigned | YES  | MUL | NULL    |                |
| leadsource_id       | bigint(20) unsigned | YES  | MUL | NULL    |                |
| industry_id         | bigint(20)          | NO   | MUL | NULL    |                |
| name                | varchar(100)        | NO   |     | NULL    |                |
| locations_count     | int(10) unsigned    | YES  |     | 0       |                |
| created             | datetime            | YES  |     | NULL    |                |
| modified            | datetime            | YES  |     | NULL    |                |
+---------------------+---------------------+------+-----+---------+----------------+

位置表：

+--------------------------+---------------------+------+-----+---------+----------------+
| Field                    | Type                | Null | Key | Default | Extra          |
+--------------------------+---------------------+------+-----+---------+----------------+
| id                       | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| location_id              | bigint(20) unsigned | NO   | MUL | NULL    |                |
| impressions_count        | bigint(20) unsigned | YES  |     | 0       |                |
| created                  | datetime            | YES  |     | NULL    |                |
| modified                 | datetime            | YES  |     | NULL    |                |
+--------------------------+---------------------+------+-----+---------+----------------+

+----------------+---------------------+------+-----+---------+----------------+
| Field          | Type                | Null | Key | Default | Extra          |
+----------------+---------------------+------+-----+---------+----------------+
| id             | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| retailer_id    | bigint(20) unsigned | NO   | MUL | NULL    |                |
| zones_count    | int(10) unsigned    | YES  |     | 0       |                |
| contacts_count | int(10) unsigned    | YES  |     | 0       |                |
| created        | datetime            | YES  |     | NULL    |                |
| modified       | datetime            | YES  |     | NULL    |                |
+----------------+---------------------+------+-----+---------+----------------+

+---------------------+---------------------+------+-----+---------+----------------+
| Field               | Type                | Null | Key | Default | Extra          |
+---------------------+---------------------+------+-----+---------+----------------+
| id                  | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| account_rep_id      | bigint(20) unsigned | YES  | MUL | NULL    |                |
| leadsource_id       | bigint(20) unsigned | YES  | MUL | NULL    |                |
| industry_id         | bigint(20)          | NO   | MUL | NULL    |                |
| name                | varchar(100)        | NO   |     | NULL    |                |
| locations_count     | int(10) unsigned    | YES  |     | 0       |                |
| created             | datetime            | YES  |     | NULL    |                |
| modified            | datetime            | YES  |     | NULL    |                |
+---------------------+---------------------+------+-----+---------+----------------+

零售商表：

+--------------------------+---------------------+------+-----+---------+----------------+
| Field                    | Type                | Null | Key | Default | Extra          |
+--------------------------+---------------------+------+-----+---------+----------------+
| id                       | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| location_id              | bigint(20) unsigned | NO   | MUL | NULL    |                |
| impressions_count        | bigint(20) unsigned | YES  |     | 0       |                |
| created                  | datetime            | YES  |     | NULL    |                |
| modified                 | datetime            | YES  |     | NULL    |                |
+--------------------------+---------------------+------+-----+---------+----------------+

+----------------+---------------------+------+-----+---------+----------------+
| Field          | Type                | Null | Key | Default | Extra          |
+----------------+---------------------+------+-----+---------+----------------+
| id             | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| retailer_id    | bigint(20) unsigned | NO   | MUL | NULL    |                |
| zones_count    | int(10) unsigned    | YES  |     | 0       |                |
| contacts_count | int(10) unsigned    | YES  |     | 0       |                |
| created        | datetime            | YES  |     | NULL    |                |
| modified       | datetime            | YES  |     | NULL    |                |
+----------------+---------------------+------+-----+---------+----------------+

+---------------------+---------------------+------+-----+---------+----------------+
| Field               | Type                | Null | Key | Default | Extra          |
+---------------------+---------------------+------+-----+---------+----------------+
| id                  | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| account_rep_id      | bigint(20) unsigned | YES  | MUL | NULL    |                |
| leadsource_id       | bigint(20) unsigned | YES  | MUL | NULL    |                |
| industry_id         | bigint(20)          | NO   | MUL | NULL    |                |
| name                | varchar(100)        | NO   |     | NULL    |                |
| locations_count     | int(10) unsigned    | YES  |     | 0       |                |
| created             | datetime            | YES  |     | NULL    |                |
| modified            | datetime            | YES  |     | NULL    |                |
+---------------------+---------------------+------+-----+---------+----------------+

我想做什么：

+--------------------------+---------------------+------+-----+---------+----------------+
| Field                    | Type                | Null | Key | Default | Extra          |
+--------------------------+---------------------+------+-----+---------+----------------+
| id                       | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| location_id              | bigint(20) unsigned | NO   | MUL | NULL    |                |
| impressions_count        | bigint(20) unsigned | YES  |     | 0       |                |
| created                  | datetime            | YES  |     | NULL    |                |
| modified                 | datetime            | YES  |     | NULL    |                |
+--------------------------+---------------------+------+-----+---------+----------------+

+----------------+---------------------+------+-----+---------+----------------+
| Field          | Type                | Null | Key | Default | Extra          |
+----------------+---------------------+------+-----+---------+----------------+
| id             | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| retailer_id    | bigint(20) unsigned | NO   | MUL | NULL    |                |
| zones_count    | int(10) unsigned    | YES  |     | 0       |                |
| contacts_count | int(10) unsigned    | YES  |     | 0       |                |
| created        | datetime            | YES  |     | NULL    |                |
| modified       | datetime            | YES  |     | NULL    |                |
+----------------+---------------------+------+-----+---------+----------------+

+---------------------+---------------------+------+-----+---------+----------------+
| Field               | Type                | Null | Key | Default | Extra          |
+---------------------+---------------------+------+-----+---------+----------------+
| id                  | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| account_rep_id      | bigint(20) unsigned | YES  | MUL | NULL    |                |
| leadsource_id       | bigint(20) unsigned | YES  | MUL | NULL    |                |
| industry_id         | bigint(20)          | NO   | MUL | NULL    |                |
| name                | varchar(100)        | NO   |     | NULL    |                |
| locations_count     | int(10) unsigned    | YES  |     | 0       |                |
| created             | datetime            | YES  |     | NULL    |                |
| modified            | datetime            | YES  |     | NULL    |                |
+---------------------+---------------------+------+-----+---------+----------------+

我正在从

零售商

表中选择所有记录。

零售商

表在

位置有许多记录

，而

区域又有许多记录

Zones

表中有一个名为

impressions\u count

的字段。我要做的是从

零售商

表中选择所有记录，同时连接到

位置

表和

区域

表

基本上，我认为我需要为

位置中的每个匹配记录返回一个总和（Zones.impressions\u count），然后为零售商中的每个记录返回一个总和。我已经把头撞在墙上有一段时间了，非常感谢任何指导
最终：我的结果集应该如下所示：
**from retailers**
id,
account_rep_id,
lead_source_id,
industry_id,
impressions_count,   // <- sum of related records in `Zones`

**来自零售商**
身份证件
客户代表id，
线索来源id，
工业署，
impressions_count，//当您加入到位置时，您可能希望在加入之前使用内联视图按位置聚合数据。。。所以
这样做是为了表之间的一对多关系不会人为地通过位置ID增加impression\u count之和
Select * 
FROM retailers R
INNER JOIN Locations L
  on R.ID = L.retailer_id
INNER JOIN 
(Select sum(impressions_count) as cnt, Location_ID from Zones group by Location_ID) as Z
  on Z.Location_ID = L.ID

现在。。如果您未在输出中显示位置，并且希望零售商提供一笔金额。。然后我们需要再次求和。。这一次，按零售商对每个位置的值求和
Select R.id
      ,R.account_rep_id
      ,R.lead_source_id
      ,R.industry_id
      ,coalesce(sum(cnt),0) as impressions_count
FROM retailers R
LEFT JOIN Locations L
  on R.ID = L.retailer_id
LEFT JOIN 
(Select coalesce(sum(impressions_count),0) as cnt, Location_ID from Zones group by Location_ID) as Z
  on Z.Location_ID = L.ID
GROUP BY R.id
        ,R.account_rep_id
        ,R.lead_source_id
        ,R.industry_id

非常接近！唯一的问题是，它不会给零售商带来零印象。这可能是固定的一个不同的连接然而。足够容易改变内部向左。我们可能需要联合起来。。。（更新）像冠军一样工作。干杯