用于组合来自两个表的数据的 SQL 查询

Question

我想合并两个不同表中的数据，它们彼此之间没有实际关系，因此我不能使用 JOIN。表结构如下：

冰淇淋

• 总计
• 广告商
• 提供者
• 供应商

零食

• 总计
• 广告商
• 提供者
• 供应商

我想运行一个查询，生成一个包含以下内容的表： ice_creams_total、snacks_total、广告商、供应商、供应商

我可以通过运行分别为每个表实现：

SELECT SUM(total) AS ice_creams_total,
       advertiser AS "advertiser::filter",
       provider AS "provider::filter",
       supplier AS "supplier::multi-filter"
FROM ice_creams
WHERE time >= now() - toIntervalHour(96)
GROUP BY integration_id,
         advertiser,
         provider,
         supplier
ORDER BY integration_id ASC,
    ice_creams_total DESC

我可以对两个表都执行此操作，并结合结果吗？

Answer 1

您可以使用union all。这是一种方法：

SELECT SUM(ice_cream_total) AS ice_creams_total,
       SUM(snaks_total) as snacks_total,
       advertiser AS "advertiser::filter", provider AS "provider::filter", supplier AS "supplier::multi-filter"
FROM ((SELECT ice_cream_total, 0 as snacks_total, integration_id, advertiser, provider, supplier
       FROM ice_creams ic
      ) UNION ALL
      (SELECT 0, total, integration_id, advertiser, provider, supplier
       FROM snacks s
      )
     ) x
WHERE time >= now() - toIntervalHour(96)
GROUP BY integration_id, advertiser, provider, supplier
ORDER BY integration_id ASC, ice_creams_total DESC

Answer 2

如果 SELECT 列匹配，您可以使用 union all 组合 2 个查询的结果。因此考虑将名称ice_creams_total 更改为total（同样将snacks_total 更改为total）并为2 个查询添加一个额外的手动字段type。 例如。

SELECT 'ice_creams' type,
...
UNION ALL
SELECT 'snacks' type,
...

查看更多：MYSQL - Concatenate two tables
另见：https://www.techonthenet.com/mysql/union_all.php