FROM { date_value | interval_value } ) select extract(year from sysdate) from dual; --当前年 select extract(month from sysdate) from dual; --本年到当月的月数 select extract(day from sysdate) from dual; --本月到当日的天数 //我们只可以从一个date类型中截取 year,month,day(date日期的格式...
Extract 属于 SQL 的 DML(即数据库管理语言)函数,同样,InterBase 也支持 Extract,它主要用于从一个日期或时间型的字段内抽取年、月、日、时、分、秒数据,因此,它支持其关健字 YEAR、MONTH、DAY、HOUR、MINUTE、SECOND、WEEKDAY、YEARDAY。 计算时间差天数 select extract(day FROM (age('2017-12-10'::date ,...
# 按年月日时分组 SELECTextract(yearfromcreated_time)asyear, extract(monthfromcreated_time)asmonth, extract(dayfromcreated_time)asday, extract(hourfromcreated_time)ashour,count(*)ascountFROMsc_appGROUPBYextract(yearfromcreated_time), extract(monthfromcreated_time), extract(dayfromcreated_time), ext...
Sql - How to extract year and month from date in, Use the date_trunc method to truncate off the day (or whatever else you want, e.g., week, year, day, etc..). Example of grouping sales from orders by month: select SUM(amount) as sales, date_trunc('month', created_at) as dat...
2.2 CURRENT_DATE(): 返回会话时区中的当前日期 2.3 CURRENT_TEMPSTAMP(): 返回会话时区中的当前时间戳 2.4 EXTRACT(): 从给定的表达式中返回制定的日期时间字段 例如: selectfrom current_timestamp) from selectMONTH from current_timestamp) from selectDAY from current_timestamp) from ...
PostgreSQL按年⽉⽇分组（关键词：extracttimeasYearMonthDay）Select EXTRACT(year from cast(joindate as timestamp)) as Year,EXTRACT(month from cast(joindate as timestamp)) as Month,EXTRACT(day from cast(joindate as timestamp)) as Day,...From Table Group by Year,Month,Day ...
首先,使用CURRENT_DATE函数获取当前日期。示例:SELECT CURRENT_DATE; 使用DATE_TRUNC函数将当前日期截断为月份,并减去一个月。示例:SELECT DATE_TRUNC('month', CURRENT_DATE) - INTERVAL '1 month'; 使用DATE_PART函数获取上个月的年份和月份。示例:SELECT DATE_PART('year', DATE_TRUNC('month', CURRENT_...
(extract (month FROM '20230416'::date))||'月'; -- 获取周:返回14 SELECT EXTRACT (week FROM '20230416'::date); -- 获取周中的周几:返回7 SELECT EXTRACT (isodow FROM '20230416'::date); -- 不同日期聚合到当周周1:如下三个都返回2023-04-10 select '20230410'::date - (EXTRACT (isodow...
extract()还有其他更强大的功能,详情请参阅官方文档,在这里只列举了一小部分: day century dow(day of week) doy(day of year) minute month year 时区转换 有些时候,时区转换对于特定时间在不同时区显示特别有用。AT TIME ZONE提供了这种功能,它是如何做到的?我们将在一个事务中进行演示,因为同一事务中now(...
The PostgreSQL DATE_PART() function is used to extract a specific part of a date and time value, such as the year, month, day, hour, minute, second, etc. Uses of DATE_PART() Function Extract Year:Retrieve the year part from a timestamp or date. ...