Question

我正在尝试获取与某个国家/地区1年时间段相关联的最高和最低值。这些数据来自一个表格。

对于某个国家/地区，我将获得帐户1的最高帐户回报和最低帐户2的帐户回报。因此，每个国家/地区都有1个结果。

我有以下内容但它无法正常工作，它实际上为我提供了错误帐户中的最高和最低值，因为它只适用于具有1年时间范围的帐户。

也忘了添加或许通过dpromo_one排序整体结果只对这些国家/地区（例如“美国”，“联合王国”，“南非”，“印度”，“澳大利亚”）仅针对这些选定国家。它变得非常复杂，它已经超越了我的头脑。

SELECT DISTINCT acc2.account_name AS account_one, acc5.account_name AS account_two,
    MAX( acc2.dpromo_rate ) AS dpromo_one, MIN( acc5.dpromo_rate ) AS dpromo_two,
    acc2.deposit_term, acc2.country
FROM accounts acc2
INNER JOIN accounts acc5 ON acc2.country = acc5.country
WHERE acc2.type =2
AND acc5.type =2
AND acc2.deposit_term =  '1 Year'
GROUP BY country

整体输出示例可能如下对于第1行：

Country    Bank    Highest    Bank             Lowest
USA        BOFA 1yr     1%      Wells Fargo 1yr 0.5% 
UK        HSBC 1yr     0.5%    Halifax 1yr     0.25% 
Australia CBA  1yr     0.4%    NAB 1yr         0.1%

例如，帐户表具有以下相关字段，例如相关的

ACCOUNT_NAME 国家 dpromo_rate deposit_term

请注意，我们同时拥有帐户和费率。我的代码虽然这样做但是不正确，这就是为什么它也解释了为什么我有重复字段名称的别名。

Answer 1

它正在做完全 MySQL所说的它会做什么。未包含在group by子句中的列具有任意值。在大多数其他数据库中，查询将因语法错误而失败。

以下是获取帐户名称的技巧：

SELECT substring_index(group_concat(acc2.account_name order by acc2.dpromo_rate desc), ',', 1) AS account_one,
       substring_index(group_concat(acc5.account_name order by acc5.dpromo_rate asc), ',', 1)  AS account_two,
       MAX( acc2.dpromo_rate ) AS dpromo_one, MIN( acc5.dpromo_rate ) AS dpromo_two,
       acc2.deposit_term, acc2.country
FROM accounts acc2
INNER JOIN accounts acc5 ON acc2.country = acc5.country
WHERE acc2.type =2 AND acc5.type =2 AND acc2.deposit_term =  '1 Year'
GROUP BY country

我认为您可以将查询简化为简单的聚合。我不明白你为什么要加入：

SELECT substring_index(group_concat(acc.account_name order by acc.dpromo_rate desc), ',', 1) AS account_one,
       substring_index(group_concat(acc.account_name order by acc.dpromo_rate asc), ',', 1)  AS account_two,
       MAX(acc.dpromo_rate) AS dpromo_one, MIN(acc.dpromo_rate) AS dpromo_two,
       acc.deposit_term, acc.country
FROM accounts acc
WHERE acc.type = 2 and acc.deposit_term =  '1 Year'
GROUP BY country;

如果您打算将存款期限仅适用于max，请将以下内容替换为：

max(case when acc.deposit_term =  '1 Year' then acc.dpromo_rate end) as dpromo_one

Answer 2

我认为这会给结果

select max(dpromo_rate), min(dpromo_rate), country, account_name, provider from accounts 
where deposit_term = '1 Year' group by country, provider, account_name

Answer 3

为您提供输出示例中的基础知识： -

SELECT DISTINCT z.county, b.account_name, b.dpromo_rate, d.account_name, d.dpromo_rate
FROM accounts z
INNER JOIN (SELECT country, type, MAX(dpromo_rate) AS MaxRate FROM accounts WHERE type = 2 AND deposit_term =  '1 Year' GROUP BY country, type) a
ON z.country = a.country AND z.type = a.type
INNER JOIN accounts b
ON a.country = b.country and a.MaxRate = b.dpromo_rate AND a.type = b.type
INNER JOIN (SELECT country, type, MIN(dpromo_rate) AS MinRate FROM accounts WHERE type = 2 AND deposit_term =  '1 Year' GROUP BY country, type) c
ON z.country = c.country AND z.type = c.type
INNER JOIN accounts d
ON c.country = d.country and c.MinRate = d.dpromo_rate AND c.type = d.type

这只是获取国家/地区，帐户名称包含最高费率，实际最高费率，帐户名称包含最低费率和实际最低费率。

不确定输出中存储术语和提供者的位置，但很容易从b或d别名表中获取。

请注意，如果您在一个共享最高或最低费率的国家/地区拥有多个帐户，这将会造成混乱。

将其限制为少数几个国家/地区并按最高费率排序： -

SELECT DISTINCT z.county, b.account_name, b.dpromo_rate, d.account_name, d.dpromo_rate
FROM accounts z
INNER JOIN (SELECT country, type, MAX(dpromo_rate) AS MaxRate FROM accounts WHERE type = 2 AND deposit_term =  '1 Year' GROUP BY country, type) a
ON z.country = a.country AND z.type = a.type
INNER JOIN accounts b
ON a.country = b.country and a.MaxRate = b.dpromo_rate AND a.type = b.type
INNER JOIN (SELECT country, type, MIN(dpromo_rate) AS MinRate FROM accounts WHERE type = 2 AND deposit_term =  '1 Year' GROUP BY country, type) c
ON z.country = c.country AND z.type = c.type
INNER JOIN accounts d
ON c.country = d.country and c.MinRate = d.dpromo_rate AND c.type = d.type
WHERE z.country IN ('united states', 'united kingdom', 'south africa', 'india', 'australia')
ORDER BY b.dpromo_rate

要将其限制为每个国家/地区，您可以执行以下操作： -

SELECT z.county, b.account_name, b.dpromo_rate, d.account_name, d.dpromo_rate
FROM accounts z
INNER JOIN (SELECT country, type, MAX(dpromo_rate) AS MaxRate FROM accounts WHERE type = 2 AND deposit_term =  '1 Year' GROUP BY country, type) a
ON z.country = a.country AND z.type = a.type
INNER JOIN accounts b
ON a.country = b.country and a.MaxRate = b.dpromo_rate AND a.type = b.type
INNER JOIN (SELECT country, type, MIN(dpromo_rate) AS MinRate FROM accounts WHERE type = 2 AND deposit_term =  '1 Year' GROUP BY country, type) c
ON z.country = c.country AND z.type = c.type
INNER JOIN accounts d
ON c.country = d.country and c.MinRate = d.dpromo_rate AND c.type = d.type
WHERE z.country IN ('united states', 'united kingdom', 'south africa', 'india', 'australia')
GROUP BY z.county
ORDER BY b.dpromo_rate

请注意，如果某个国家/地区的2个帐户具有相同的费率，这是该国家/地区的最高费率，那么只会返回一个帐户。返回哪一个不确定。

MySQL MAX与第二列关联

3 个答案: