select “sysdate” from dual; -->ORA-00911: invalid character 如下则不会输出时间,只会输出sysdate这个字符串。 select ‘sysdate’ from dual; -->sysdate 1.2、双引号引住字段名 select * from emp where ENAME = 'ALLEN'; -->ok select * from emp where “ENAME” = 'ALLEN'; -->ok 因为双引...
select to_char(sysdate,'yyyy-mon-dd day') from dual --输入当前的系统日期,格式为 yyyy-mon-dd-dy select to_char(sysdate,'yyyy-mon-dd-dy') from dual --输入当前的系统日期,格式为 yyyy-mon-dd-dy-d select to_char(sysdate,'yyyy/mon/dd/dy/d') from dual --ddspth 日期的英文显示 --输...
Select SYSDATE FROM dual; PostgreSQL Select CURRENT_DATE; Select NOW();返回日期时间还包括时区 2. 操作时间的获取子域 1 2 3 4 5 6 oracle : Select TO_CHAR(SYSDATE,'Day') FROM dual; PostgreSQL : Select DATE_PART('dow',date 'now'); //dow = day of week Select DATE_PART('hour', ti...
SQL> select sysdate from dual; SYSDATE 03/01/2020 09:56:53 SQL> alter session set time_zone = ‘-08:30’; Session altered. SQL> (select ‘dbtimezone’ as config, dbtimezone as offset from dual) union (select ‘sessiontimezone’ as config, sessiontimezone as offset from dual); CONF...
SQL> select sysdatefromdual;SYSDATE---24-8月 -16SQL> selectadd_months(sysdate,2)fromdual;ADD_MONTHS(SYS---24-10月-16SQL> selectadd_months(sysdate, -2)fromdual;ADD_MONTHS(SYS---24-6月 -16SQL> selectadd_months(to_date('2016/08/01','YYYY/MM/DD'), -1)fromdual;ADD_MONTHS(TO_-...
sysdate - timestamp:一致 Oracle 代码语言:javascript 代码运行次数:0 运行 AI代码解释 select sysdate - timestamp '2015-04-10 14:52:19.000' from dual; +000001906 15:57:05.000000000 Postgresql 代码语言:javascript 代码运行次数:0 运行 AI代码解释 select CURRENT_TIMESTAMP - timestamp '2015-04-10 14...
Oracle PostgreSQL select sysdate from dual select ‘now’::datetime There is no “dual” table Unlike other RDBMS, PostgreSQL allows a “select” without the ”from” clause. This use does not affect portability because the syntax to get current time is already DBMS specific. CREATE SEQUENCE ...
SQL> select extract(year from sysdate) from dual;--获得年份 EXTRACT(YEARFROMSYSDATE) --- 2012 SQL> select extract(month from sysdate) from dual;--获得月份 EXTRACT(MONTHFROMSYSDATE) --- 9 SQL> select extract(day from sysdate) from dual;--获得日 EXTRACT...
Oracle的delete语句的FROM关键字可以省略,迁移至PostgreSQL需补充上。 NOLOGGING关键字 Oracle在执行INSERT语句时,可以通过指定NOLOGGING关键字来减少日志记录,提升操作性能。PostgreSQL不支持此关键字。 AS关键字 INSERT INTO 后面不需要添加as关键字,insert into ... as select... 修改为insert into... select... ...
...答案部分 Oracle的日期默认显示为以下格式: SYS@PROD1> select sysdate from dual; SYSDATE --- 22-DEC-17 阅读不方便,此时可以通过设置...NLS_DATE_FORMAT来让日期显示更人性化,可以有如下几种方式: ① 在会话级别运行命令:“ALTER SESSION SET NLS_DATE_FORMAT='YYYY-MM-DD HH24:...MI:SS';”,...