mysql - SQL按开发类型分组和值求和

Question

我正在开发一个 API 来返回建筑项目列表。

SELECT 
`sample`.`Development Type` AS 'Development Type',
`sample`.`Postcode` AS 'Postcode',
`sample`.`Value Desc` AS 'Value Desc'
FROM
`sample`
WHERE `sample`.`Postcode` LIKE '%SW1%'

这会返回一个建筑项目列表。

Development Type          | Postcode      | Value Desc

Refurbishment & Extension | SW1E 6LB      | 400,000
Refurbishment & Extension | SW1E 6LB      | 400,000
Refurbishment & Extension | SW1X 8AL      | 75,000
Refurbishment & Extension | SW1X 8AL      | 75,000 
Refurbishment & Extension | SW1P 3RE      | 225,000
Refurbishment & Extension | SW1P 3RE      | 225,000
Extension                 | SW1X 7QU      | 200,000
Extension                 | SW1X 7QU      | 200,000
Refurbishment             | SW1X 8AL      | 75,000

我需要修改查询以获得这样的输出。

Development Type          | Sum Value Desc

Refurbishment & Extension | 700,000
Extension                 | 200,000
Refurbishment             | 75,000

--所以按开发类型分组--删除重复的结果(可能是我应该做一个 where 查询的标志，以千为单位求和以处理逗号)

Answer 1

这将是一个简单的 GROUP BY 查询，如果不是因为每条记录似乎重复出现的话。但这可以通过首先使用带有 SELECT DISTINCT 的子查询来删除重复项，然后从此子查询分组以获得所需的总和来解决:

SELECT t.`Development Type`, FORMAT(SUM(t.`Value Desc`), 0)
FROM
(
    SELECT DISTINCT `Development Type`, `Postcode`, `Value Desc`
    FROM sample
) t
GROUP BY t.`Development Type`
ORDER BY SUM(t.`Value Desc`) DESC

点击下面的链接获取正在运行的演示:

SQLFiddle

更新:

由于您的源数据可能是 CSV 格式，您可以将外部 SELECT 语句更改为以下内容以处理逗号:

SELECT t.`Development Type`,
       FORMAT(SUM(CAST(REPLACE(`Value Desc`, ',' , '') AS UNSIGNED)), 0)

您还可以将 ORDER BY 子句更改为:

ORDER BY SUM(CAST(REPLACE(`Value Desc`, ',' , '') AS UNSIGNED)) DESC