create or replace function sys_date return date is begin return sysdate; end; select to_char(sys_date,'hh:mi:ss') from all_objects; 12. 获得小时数 SELECT EXTRACT(HOUR FROM TIMESTAMP '2001-02-16 2:38:40') from offer SQL> select sysdate ,to_char(sysdate,'hh') from dual; SYSDATE T...
date_part函数是 SQL 标准extract函数的同义词。 例如,date_part('year', CURRENT_DATE)等效于extract(YEAR FROM CURRENT_DATE) 示例 SQL复制 >SELECTdate_part('YEAR',TIMESTAMP'2019-08-12 01:00:00.123456'); 2019 >SELECTdate_part('Week',TIMESTAMP'2019-08-12 01:00:00.123456'); 33 >SELECTdate_...
extract(field FROM x) → bigint【注:field不带引号!】 year(x),month(x),day(x) 1. 2. eg: select extract(year from current_date), year(current_date), extract(month from current_date), month(current_date), extract(day from current_date), day(current_date); ---+---+---+---+-...
1)DAY(DATE/DATETIME EXPRESSION) 返回指定表达式中的当月几号 2)MONTH(DATE/DATETIME EXPRESSION) 返回指定表达式中的月份 3)YEAR(DATE/DATETIME EXPRESSION) 返回指定表达式中的年份 4)WEEKDAY(DATE/DATETIME EXPRESSION) 返回指定表达式中的当周星期几 5)DATE(NOT DATE EXPRESSION) 返回指定表达式代表的日期值 6)TO...
11 select to_char(sysdate,'hh:mi:ss') TIME from all_objects 注意:第一条记录的TIME 与最后一行是一样的 可以建立一个函数来处理这个问题 create or replace function sys_date return date is begin return sysdate; end; 1. 2. 3. 4.
Retrieving Month and Date from Year in Oracle Database: A Rephrased Approach, Oracle: How to Determine Years from Date Differences, Creating a Date Column in Oracle SQL Using Month and Year: A Step-by-Step Guide, Oracle: Combining Year, Month, and Day Co
MySQL uses the TIMESTAMPDIFF function to calculate the difference between two dates or datetimes: SELECT TIMESTAMPDIFF(unit, startdate, enddate) FROM table_name; Copy Where unit represents the unit of time, like YEAR, QUARTER, MONTH, WEEK, DAY, HOUR, MINUTE, or SECOND. Note that TIMESTAMP...
SQL_CVT_DATE (ODBC 1.0)SQL_CVT_DECIMAL (ODBC 1.0)SQL_CVT_DOUBLE (ODBC 1.0)SQL_CVT_FLOAT (ODBC 1.0)SQL_CVT_INTEGER (ODBC 1.0)SQL_CVT_INTERVAL_YEAR_MONTH (ODBC 3.0)SQL_CVT_INTERVAL_DAY_TIME (ODBC 3.0)SQL_CVT_LONGVARBINARY (ODBC 1.0)SQL_CVT_LONGVARCHAR (ODBC 1.0)SQL_CVT_NUMERIC (...
SQL_CONVERT_DATE SQL_CONVERT_DECIMAL SQL_CONVERT_DOUBLE SQL_CONVERT_FLOAT SQL_CONVERT_INTEGER SQL_CONVERT_INTERVAL_DAY_TIME SQL_CONVERT_INTERVAL_YEAR_MONTH SQL_CONVERT_LONGVARBINARY SQL_CONVERT_LONGVARCHAR SQL_CONVERT_NUMERIC SQL_CONVERT_REAL SQL_CONVERT_SMALLINT SQL_CONVERT_TIME SQL_CONVERT_TIMESTAM...
SELECT CAST('12-12-2023' AS date); Copy Similarly, you can also use CAST to extract the date from your current date and time. SELECT CAST(getdate() AS date); Copy CONVERT Another function is CONVERT, an in-built function that allows users to convert an expression from one data type ...