mysql - 在mysql的子查询中使用相同的字段

Question

我怎样才能做这样的事情？

INSERT INTO age.page(domain,title_count,youtube_count,ipaddress,updated)
SELECT * FROM 
(
    SELECT domain,
    COUNT(domain) AS titlecount,
   (SELECT COUNT(*) FROM table2 WHERE title = table1.title) AS YoutubeCount, ipaddress
    NOW() AS timeNow
    FROM table1
    GROUP BY domain
    ORDER BY title DESC
) a;

我想使用子查询来获取不同表的计数，但使用主查询中的相同字段。

我想这样做的原因是我不必运行两个查询，而是只运行一个查询。

Answer 1

您可以在子查询中执行此COUNT操作，然后将其与第一个表JOIN:

INSERT INTO age.page(domain, title_count, youtube_count, ipaddress, updated)
SELECT * FROM 
(
    SELECT 
      domain,
      COUNT(domain) AS titlecount,
      t2.titlecount AS YoutubeCount, 
      ipaddress,
      NOW() AS timeNow
    FROM table1
    INNER JOIN
    (
       SELECT title, COUNT(*) Titlecount
       FROM table2 
       GROUP BY title
    ) AS t2 ON t2.title = table1.title   
    GROUP BY domain
    ORDER BY table1.title DESC
) a;