Mysql按天按月按年分組查詢

下面語句主要用於根據數據庫字段進行按天、按月、按年分組統計時的查詢，僅做個人收藏備用。

1、如果時間字段類型為date或datetime：

//按周查詢
SELECT DATE_FORMAT(create_time,'%Y%u') weeks,COUNT(id) COUNT FROM role GROUP BY weeks;
//按天查詢
SELECT DATE_FORMAT(create_time,'%Y%m%d') days,COUNT(id) COUNT FROM role GROUP BY days;
//按月查詢
SELECT DATE_FORMAT(create_time,'%Y%m') months,COUNT(id) COUNT FROM role GROUP BY months

2、如果時間字段為時間戳（timestamp）或int表示的時間戳：

//按周查詢
SELECT FROM_UNIXTIME(create_time,'%Y%u') weeks,COUNT(id) COUNT FROM role GROUP BY weeks;
//按天查詢
SELECT FROM_UNIXTIME(create_time,'%Y%m%d') days,COUNT(id) COUNT FROM role GROUP BY days;
//按月查詢
SELECT FROM_UNIXTIME(create_time,'%Y%m') months,COUNT(id) COUNT FROM role GROUP BY months