MySQL Join 三个不同的结果并计数答案

【问题标题】：MySQL Join three different results and countMySQL Join 三个不同的结果并计数
【发布时间】：2013-09-12 11:20:19
【问题描述】：

从三个不同的表中提取了三个结果。

每个表都是一个产品：loans、credits 和 discounts。

贷款和信用得到以下数据：clientid、type、productid、date & expiration（还有几天）。获得的折扣：clientid、date 和 expiration。

结果是每个客户的产品在 10 天（或更短）内到期并在两个日期之间注册的次数（计数）。示例（仅用于贷款）：

SELECT clientid, COUNT(*)
FROM loans
WHERE ((type LIKE 'TITULAR') AND(date BETWEEN 'ccyy-mm-dd' AND 'ccyy-mm-dd') AND (expires <= 10))
GROUP BY clientid
ORDER BY clientid;

显然，并非所有客户都同时获得贷款、信贷或折扣，但我需要得到一个结果，即在限制日期内任何客户的任何产品在 10 天或更短时间内到期的次数总和.

因此，例如，如果客户 #200 获得 3 笔贷款、2 笔信贷和 1 次折扣；所有这些都在 date1 和 date2 之间，到期时间等于或小于 10；结果应该是 6。

到目前为止我已经尝试过：

SELECT loansr.clienteid, (loansr.count + creditsr.count + discountsr.count)
FROM
    (SELECT clienteid, COUNT(*) AS "count"
    FROM loans
    WHERE (type LIKE 'TITULAR') 
    AND (date BETWEEN '2009-08-01' AND '2009-10-30')
    AND (expires <= 10)
    GROUP BY clienteid) loansr,
    (SELECT clienteid, COUNT(*) AS "count"
    FROM credits
    WHERE (type LIKE 'TITULAR') 
    AND (date BETWEEN '2009-08-01' AND '2009-10-30')
    AND (expires <= 10)
    GROUP BY clienteid) creditsr,
    (SELECT clienteid, COUNT(*) AS "count"
    FROM discounts
    WHERE (date BETWEEN '2009-08-01' AND '2009-10-30')
    AND (expires <= 10)
    GROUP BY clienteid) discountsr
WHERE
    (loansr.clienteid = creditsr.clienteid = discountsr.clienteid)
ORDER BY loansr.clienteid;

编辑 18:25 我认为如果我使用 UNION ALL 混合三个结果，然后按 clienteid 分组，我会得到我想要的，不是吗？

SELECT clienteid AS "CLIENTE", SUM(COUNT) AS  "NUM_VECES_INCI_10_ACT_U3M" FROM
    ((SELECT clienteid, COUNT(*) AS "COUNT"
    FROM loans
    WHERE (titularidad_tipo LIKE 'TITULAR') 
    AND (date BETWEEN '2009-08-01' AND '2009-10-30')
    AND (expires >= 11)
    GROUP BY clienteid)
        UNION ALL
    (SELECT clienteid, COUNT(*) AS "COUNT"
    FROM credits
    WHERE (titularidad_tipo LIKE 'TITULAR') 
    AND (date BETWEEN '2009-08-01' AND '2009-10-30')
    AND (expires >= 11)
    GROUP BY clienteid)
        UNION ALL
    (SELECT clienteid, COUNT(*) AS "COUNT"
    FROM discounts
    WHERE (date BETWEEN '2009-08-01' AND '2009-10-30')
    AND (expires >= 11)
    GROUP BY clienteid)) orig
GROUP BY clienteid
ORDER BY clienteid;

【问题讨论】：

标签： mysql join sum

【解决方案1】：

如果可以的话，我会在评论中发布:) 如果你使用 UNION ALL，你应该得到想要的结果。尽管要确保为表 loanr、credits 和（date，expires）表提供适当的索引（我建议为 titularidad_tipo、date、expires）和 discounts 表。如果你有适当的索引，你的结果会很快出现。

【讨论】：