MySQL UNION表按列分组

时间:2018-05-20 12:13:34

标签: mysql

我有两张表searchesrecommended_searches。两者都有两列idkeyword

搜索表

id | keyword 
1  | one 
2  | two 
3  | one 
4  | one 
5  | two
6  | one

recommended_searches table

id | key 
1  | two 
2  | two 
3  | one 
4  | two 
5  | two
6  | one

我使用此查询返回搜索表中每个关键字的计数

SELECT keyword, count(*) as cnt FROM searches GROUP BY keyword ORDER by cnt DESC

以及此推荐

的查询
SELECT keyword, count(*) as cnt FROM recommended_searches GROUP BY keyword ORDER by cnt DESC

我希望在这两个表上按键分组,但搜索表为cnt,推荐搜索为recommended_cnt。这是我可以根据表格类型进行ORDER BY,例如按推荐搜索排序。

SELECT keyword, count(*) as cnt FROM searches
UNION ALL
SELECT keyword, count(*) as recommended_cnt FROM recommended_searches
GROUP BY keyword ORDER by recommended_cnt DESC

如何同时返回cntrecommended_cnt?我试过上面而不工作。

我想要一个像

这样的结果
Array(
[keyword] => one
[cnt] => 4
[recommended_cnt] => 2
);

Array(
[keyword] => two
[cnt] => 2
[recommended_cnt] => 4
);

2 个答案:

答案 0 :(得分:2)

将计数放在两个子查询中的不同列中。

SELECT `key`, MAX(cnt) AS cnt, MAX(recommended_cnt) AS recommended_cnt
FROM (
    SELECT `keyword` AS `key`, COUNT(*) AS cnt, 0 AS recommended_cnt
    FROM searches
    GROUP BY `key`
    UNION ALL
    SELECT `key`, 0 AS cnt, COUNT(*) AS recommended_cnt
    FROM recommended_searches
    GROUP BY `key`
) AS x
GROUP BY `key`

DEMO

答案 1 :(得分:0)

你想要的不是UNION,你想在它们之间加入。

SELECT a.keyword, a.cnt AS cnt, b.cnt AS cnt_recommended
FROM
  (SELECT keyword, count(*) as cnt FROM searches GROUP BY keyword ORDER by cnt DESC) as a
LEFT OUTER JOIN
  (SELECT keyword, count(*) as cnt FROM recommended_searches GROUP BY keyword ORDER by cnt DESC) as b
  ON a.keyword = b.keyword
GROUP BY a.keyword
ORDER BY ...

这将加入两个查询并分别为它们提供计数。根据您的要求,连接类型可能不同。

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