-- 1.獲取當前日期時間
select sysdate() from dual;
select current_date() from dual;
-- 獲取時間戳
select current_timestamp() from dual;
-- 2,日期的擷取
-- 獲取到當前日期時間所在的年份
select extract(year from sysdate()) from dual;
select extract(month from sysdate()) from dual;
select extract(day from sysdate()) from dual;
-- 3.日期的截斷,這個四捨五入沒用
select round(sysdate(),'year') from dual;
select truncate(sysdate(),'year')from dual;
--select ename,empno months_between(sysdate(),hiredate) months from t_emptest;
select * from t_emptest;
select sysdate() from dual;
select * from t_emptest where sal = '3000';
select * from t_emptest where sal = 3000;
select 100 + 2000 from dual;
select '100' + 2000 from dual;
select 100 + cast('200' as int) from dual;
select cast(100 as varchar)+100 from dual;
select cast(100 as char) + 100 from dual;
select cast(date_cloumn as signed) as date from t_date ;
select cast(timstamp_cloumn as time) as date from t_date ;
-- 獲取到最大的
select greatest(10,'101',9) from dual;
-- 找到最小的，按照accii碼值來比較
select least('中','abc','ab',1000) from dual
select 1 + null from dual;
MySql 學習筆記《日期》
昨天 select date add curdate interval 1 day select date sub curdate interval 1day 今天 select curdate select current date 明天 select date add curdate inter...
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