MySQL 每个办公室邮政编码的查询频率

Question

我正在尝试编写一个 MySQL 查询，以查看哪些邮政编码对我们的客户来说最常出现，并且需要帮助来完成它。我的 select 语句末尾的 office 字段可以是每个邮政编码 1 到 10 种可能性。

我将如何修复此查询以获得最常见的邮政编码以及 10 个可能的办公室中的哪个恰好在该邮政编码中有一个位置？

SELECT SUBSTRING(zip_code, 1, 5) AS zip, 
COUNT(*) AS freq, office
FROM customer_billing 
WHERE status != 'deleted'
GROUP BY zip
ORDER BY freq DESC

我正在寻找的示例输出：

zip     freq     office
----    ----     ----
92101    450     office_A, office_B
02124    300     office_A, office_C, office_D
07713    110     office_B

Answer 1

使用 GROUP_CONCAT 和 DISTINCT。使用 DISTINCT 是必要的，因为对于给定的邮政编码，给定的办公室可能会出现多次。

SELECT SUBSTRING(zip_code, 1, 5), COUNT(*) AS freq,
    GROUP_CONCAT(DISTINCT office ORDER BY office DESC SEPARATOR ',')
FROM customer_billing
WHERE status != 'deleted'
GROUP BY SUBSTRING(zip_code, 1, 5)
ORDER BY freq DESC

Answer 2

您可以使用group_concat

This function returns a string result with the concatenated non-NULL values from a group. It returns NULL if there are no non-NULL values. The full syntax is as follows:

SELECT SUBSTRING(zip_code, 1, 5) AS zip, 
COUNT(*) AS freq, GROUP_CONCAT(office)
FROM customer_billing 
WHERE status != 'deleted'
GROUP BY zip
ORDER BY freq DESC

MySQL 每个办公室邮政编码的查询频率

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