mysql今天0点

mysql按照日或者月进行统计的时候，如果当天没有记录，会导致日期缺少，这里采用关联方式进行模拟日期表

1、生成日期表

ｓｅｌｅｃｔ @cdate:=DATE_ADD(@cdate,INTERVAL -1 day) as DAY_TIMEfrom(ｓｅｌｅｃｔ @cdate:=DATE_ADD(STR_TO_DATE(‘2021-10-31‘,‘%Y-%m-%d‘),INTERVAL 1 day)from b2b_order limit 31) aa where @cdate>‘2021-10-01‘ and @cdate‘2021-10-01‘ and @cdate= STR_TO_DATE(‘2021-10-01‘,‘%Y-%m-%d‘) and t.ORDER_DATE‘2021-01-01‘ and @cdate‘2021-01-01‘ and @cdate= STR_TO_DATE(‘2021-01-01‘,‘%Y-%m-%d‘)and t.ORDER_DATE