傳遞結果從一個子查詢的IN子句中的另一個子查詢在MySQL

Question

不知道這是可能的，但如果是，就會使我的查詢速度要快得多。

基本上我有這樣的查詢：

SELECT * 
    FROM (SELECT bar.id 
      FROM pivot_table 
      WHERE foo.id = x) t1 
    JOIN (SELECT count(*) c1, bar.id 
      FROM table 
     GROUP BY bar.id) t2 ON t1.id = t2.id 
    JOIN (SELECT count(*) c2, bar.id 
      FROM another_table 
     GROUP BY bar.id) t3 ON t1.id = t3.id 

但是，這是相當緩慢的，因爲table和another_table是巨大的。但實際上，我只對t1中的查詢產生的值感興趣。因此，如果我能以某種方式將這些結果納入t2和t3的IN子句中，查詢應該顯着加快。

這可能嗎？

---

不太清楚我猜。好的我在想的是將查詢改爲類似於：

SELECT * 
    FROM (GROUP_CONCAT (bar.id) as results 
       FROM pivot_table 
       WHERE foo.id = x) t1 
     JOIN (SELECT count(*) c1, bar.id 
       FROM table 
       WHERE bar.id IN (*results from t1*) 
       GROUP BY bar.id) t2 ON t1.id = t2.id 
     JOIN (SELECT count(*) c2, bar.id 
       FROM another_table 
       WHERE bar.id IN (*results from t1*) 
       GROUP BY bar.id) t3 ON t1.id = t3.id 

可能會更快，因爲它縮小了在t2和t3中掃描的行數。情況不是這樣嗎？

---

每個人都希望看到它，所以這裏是完整的查詢：

SELECT (k_group.count/jk_group.count) * (s_group.count/jk_group.count) AS ratio, 
     jk_group.k_id               , 
     jk_group.s_id 
FROM 
     -- find the keywords for the job 
     (SELECT jk.keyowrd_id AS k_id 
     FROM jobs_keywords jk 
     WHERE job_id = 50100 
     ) 
     extracted_keywords 
     -- calculate the necessary values using group_by functions 
     INNER JOIN 
        (SELECT COUNT(*) count, 
          skill_id AS s_id , 
          keyword_id AS k_id 
        FROM  jobs_keywords jk 
          JOIN jobs_skills js 
          ON  js.job_id = jk.job_id 
          JOIN job_feed_details d 
          ON  d.job_id = js.job_id 
        WHERE d.moderated  = 1 
        GROUP BY skill_id, 
          keyword_id 
       ) 
        jk_group 
     ON  extracted_keywords.k_id = jk_group.k_id 
     INNER JOIN 
        (SELECT COUNT(*)  count, 
          keyword_id AS k_id 
        FROM  jobs_keywords jk 
          JOIN job_feed_details d 
          ON  d.job_id = js.job_id 
        WHERE d.moderated  = 1 
        GROUP BY keyword_id 
       ) 
        k_group 
     ON  jk_group.k_id = k_group.k_id 
     INNER JOIN 
        (SELECT COUNT(*) count, 
          skill_id AS s_id 
        FROM  jobs_skills js 
          JOIN job_feed_details d 
          ON  d.job_id = js.job_id 
        WHERE d.moderated  = 1 
        GROUP BY skill_id 
       ) 
        s_group 
     ON  jk_group.s_id = s_group.s_id 
ORDER BY ratio DESC 
LIMIT 25 

Answer 1

我能做到什麼，我試圖做像這樣：

SELECT * 
    FROM (@var:=GROUP_CONCAT(bar.id) as results 
       FROM pivot_table 
       WHERE foo.id = x) t1 
     JOIN (SELECT count(*) c1, bar.id 
       FROM table 
       WHERE bar.id IN (@var) 
       GROUP BY bar.id) t2 ON t1.id = t2.id 
     JOIN (SELECT count(*) c2, bar.id 
       FROM another_table 
       WHERE bar.id IN (@var) 
       GROUP BY bar.id) t3 ON t1.id = t3.id 

但在速度方面的優勢不是太顯著。我現在已經放棄了一種查詢方法，以支持許多較小的查詢，而且這樣更好。

Answer 2

修訂給出實際的查詢

我想你可以消減查詢到：

Select jk.Count(Distinct jk.keyword_id) 
     * jk.Count(Distinct js.skill_id) 
     /Power(Count(*), 2) 
     As ratio 
    , js.skill_id 
    , jk.keyword_id 
From jobs_keywords As jk 
    Join jobs_skills As js 
     On js.job_id = jk.job_id 
Where jk.job_id =50100 
Group By js.skill_id, jk.keyword_id 
Order By ratio Desc 
Limit 25 

Answer 3

SELECT COUNT(t1.id) c1, COUNT(t2.id) c2, COUNT(t3.id) c3, t1.id 
FROM pivot_table t1 
JOIN table t2 ON t1.id=t2.id 
JOIN another_table t3 ON t3.id=t1.id where t1.id=x group by t1.id 

請確保pivot_table.id，table.id和another_table.id被索引

有關查詢： 查詢的問題是driverd表使用加入緩衝液，讓你的查詢速度快，你應該增加你的加入緩衝區大小