Question

我有3张桌子 - News, Content and Edits。

每个表格中的每一行都包含一个user_id字段。

我想要做的是列出这3个表的主要贡献者。

因此，我需要计算每个表中每个不同user_id出现的次数，并从最高计数到最低计数。

Answer 1

像这样：

SELECT 
    user_id,
    COUNT(*) AS all_actions 
FROM (
    SELECT user_id FROM News
    UNION ALL
    SELECT user_id FROM Content
    UNION ALL
    SELECT user_id FROM Edits
) tmp_table
GROUP BY user_id
ORDER BY all_actions DESC

Answer 2

这应该这样做。

SELECT all_user_ids.user_id as `user_id`, COUNT(all_user_ids.user_id) as `count`
FROM
(SELECT user_id FROM news
UNION ALL
SELECT user_id FROM content
UNION ALL
SELECT user_id FROM edits) AS all_user_ids
GROUP BY `user_id`
ORDER BY `count` DESC

Answer 3

这将是每个表的实例

SELECT DISTINCT(COUNT(user_id)) as num FROM news GROUP BY user_id ORDER BY num DESC LIMIT 0,3

按3个表的不同行数排序？

3 个答案: