mysql怎么根据date做年，月，日分组统计查询

使用 YEAR(), MONTH(), DAY() 来获取年月日

SELECT YEAR(application_date) as years, count(1) FROM patent GROUP BY YEAR(application_date) ORDER BY years -- YEAR(application_date)   获取年份 -- MONTH(application_date)　获取月份 -- DAY(application_date)    获取日

使用 date_format(application_date, '%Y')，可自定义日期格式

SELECT date_format(application_date, "%Y") as year, count(1) FROM patent GROUP BY date_format(application_date, "%Y")

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