按月和年分组

Question

我正在尝试计算按月和年分组的实例。

SELECT 
    (MONTH(CAST(t1.some_date as DATE)) + ' ' + YEAR(CAST(t1.some_date as DATE))) as Issue_Month,
    COUNT(*) as c
FROM
    (sub query) t1
GROUP BY 
    (MONTH(CAST(t1.some_date as DATE)) + ' ' + YEAR(CAST(t1.some_date as DATE)))

错误行 2：“+”不能应用于 bigint、varchar(1)

我曾尝试换+为&与||构建所需的字符串，但我有没有运气。

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我如何生成如下表：

Month Year  |  c

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我如何制作这张表：

Month  |  Year  |  c

Answer 1

您可以使用date_format()：

SELECT 
    date_format(CAST(t1.some_date as DATE), '%m %Y') as Issue_Month,
    COUNT(*) as c
FROM
    (sub query) t1
GROUP BY 
    date_format(CAST(t1.some_date as DATE), '%m %Y')