Question

我正在尝试编写一个MySQL查询，以查看哪些邮政编码最常出现给我们的客户，并需要帮助才能完成。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。

我如何修复此查询以获取最常用的邮政编码，以及10个可能的办事处中哪些恰好在该邮政编码中有位置？

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我正在寻找的样本输出：

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

Answer 1

将GROUP_CONCAT与DISTINCT一起使用。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多次出现。

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

此函数返回带有连接非NULL的字符串结果一组中的值。如果没有非NULL值，则返回NULL。完整语法如下：

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

每个局的邮政编码的MySQL查询频率

2 个答案: