SQL Oracle 中的 DATEDIFF 函数
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DATEDIFF function in Oracle
提问by user3601310
I need to use Oracle but DATEDIFF function doesn't work in Oracle DB.
我需要使用 Oracle 但 DATEDIFF 函数在 Oracle DB 中不起作用。
How to write the following code in Oracle? I saw some examples using INTERVAL or TRUNC.
下面的代码在oracle中怎么写？我看到了一些使用 INTERVAL 或 TRUNC 的示例。
SELECT DATEDIFF ('2000-01-01','2000-01-02') AS DateDiff;
回答by Mureinik
In Oracle, you can simply subtract two dates and get the difference in days. Also note that unlike SQL Server or MySQL, in Oracle you cannot perform a selectstatement without a fromclause. One way around this is to use the builtin dummy table, dual:
在 Oracle 中，您可以简单地减去两个日期并得到天数的差值。另请注意，与 SQL Server 或 MySQL 不同，在 Oracle 中，您不能执行select没有from子句的语句。解决此问题的一种方法是使用内置虚拟表dual：
SELECT TO_DATE('2000-01-02', 'YYYY-MM-DD') -
TO_DATE('2000-01-01', 'YYYY-MM-DD') AS DateDiff
FROM dual
回答by a_horse_with_no_name
Just subtract the two dates:
只需减去两个日期：
select date '2000-01-02' - date '2000-01-01' as dateDiff
from dual;
The result will be the difference in days.
结果将是天数的差异。
More details are in the manual:
https://docs.oracle.com/cd/E11882_01/server.112/e41084/sql_elements001.htm#i48042
手册中有更多详细信息：https:
//docs.oracle.com/cd/E11882_01/server.112/e41084/sql_elements001.htm#i48042
回答by Patrick Hofman
You can simply subtract two dates. You have to cast it first, using to_date:
您可以简单地减去两个日期。您必须首先使用to_date：
select to_date('2000-01-01', 'yyyy-MM-dd')
- to_date('2000-01-02', 'yyyy-MM-dd')
datediff
from dual
;
The result is in days, to the difference of these two dates is -1(you could swap the two dates if you like). If you like to have it in hours, just multiply the result with 24.
结果以天为单位，这两个日期的差为-1（如果您愿意，可以交换两个日期）。如果您喜欢以小时为单位，只需将结果乘以 24。
回答by pavani chinthalapalli
We can directly subtract dates to get difference in Days.
我们可以直接减去日期以获得天数的差异。
SET SERVEROUTPUT ON ;
DECLARE
V_VAR NUMBER;
BEGIN
V_VAR:=TO_DATE('2000-01-02', 'YYYY-MM-DD') - TO_DATE('2000-01-01', 'YYYY-MM-DD') ;
DBMS_OUTPUT.PUT_LINE(V_VAR);
END;
