获取时间格式

SELECT NOW(),CURDATE(),SYSDATE(),CURTIME() FROM DUAL;

NOW( ) 和 SYSDATE( ) 的区别

SELECT NOW(),SYSDATE(),SLEEP(3),NOW(),SYSDATE()

NOW( ) 和 SYSDATE( ) 虽然都表示当前时间，但使用上有一点点区别：

1. NOW( ) 取的是语句开始执行的时间
2. SYSDATE( ) 取的是动态的实时时间

实现二个日期时间差

TIMESTAMPDIFF(时间差类型,时间1,时间2)

时间差类型：

select TIMESTAMPDIFF(SECOND,send_time,finish_time) from tms_order where finish_time > send_time

SECOND 秒
MINUTE 分钟
HOUR 时间
DAY 天
MONTH 月
YEAR 年

SELECT TIMESTAMPDIFF(MINUTE,"2021-01-01 10:00:01","2021-01-01 10:01:01") FROM DUAL;

mysql查询今天、昨天、7天、近30天、本月、上一月 数据
今天
select from 表名 where to_days(时间字段名) = to_days(now());
昨天
SELECT FROM 表名 WHERE TO_DAYS( NOW( ) ) - TO_DAYS( 时间字段名) = 1
近7天
SELECT FROM 表名 where DATE_SUB(CURDATE(), INTERVAL 7 DAY) <= date(时间字段名)
查询当前这周的数据
SELECT name,submittime FROM enterprise WHERE YEARWEEK(date_format(submittime,’%Y-%m-%d’)) = YEARWEEK(now());
查询上周的数据
SELECT name,submittime FROM enterprise WHERE YEARWEEK(date_format(submittime,’%Y-%m-%d’)) = YEARWEEK(now())-1;
近30天
SELECT FROM 表名 where DATE_SUB(CURDATE(), INTERVAL 30 DAY) <= date(时间字段名)
本月
SELECT FROM 表名 WHERE DATE_FORMAT( 时间字段名, ‘%Y%m’ ) = DATE_FORMAT( CURDATE( ) , ‘%Y%m’ )
上一月
SELECT FROM 表名 WHERE PERIOD_DIFF( date_format( now( ) , ‘%Y%m’ ) , date_format( 时间字段名, ‘%Y%m’ ) ) =1
查询距离当前现在6个月的数据
select name,submittime from enterprise where submittime between date_sub(now(),interval 6 month) and now();

查询本季度数据
select from ht_invoice_information where QUARTER(create_date)=QUARTER(now());
#查询上季度数据
select from ht_invoice_information where QUARTER(create_date)=QUARTER(DATE_SUB(now(),interval 1 QUARTER));
#查询本年数据
select from ht_invoice_information where YEAR(create_date)=YEAR(NOW());
#查询上年数据
select from ht_invoice_information where year(create_date)=year(date_sub(now(),interval 1 year));