Oracle：VarChar（hh24：mm：ss）-时间戳，如何？

Question

I'm used to SQL Server and datediff, time data types. Pulling my hair out trying to figure this out.

Column 1: Timestamp Column 2: Varchar(200) in the form HH24:MM:SS

Trying to do:

SELECT Varchar(200) - Timestamp AS Difference
FROM table

Can't figure out the right way to do this, queries are getting ridiculously complicated.

Answer 1

Here is a possible oracle select statement to solve your problem.

A simple explanation of the code: select to_date(char) - to_date(to_char(date)) as difference from table; you need to convert the varchar(200) to date and convert the timestamp to the same date format in varchar then finally convert the timestamp varchar into date format.

That should work.

select to_date('17:15:30', 'HH24:MI:SS')- to_date(to_char(systimestamp, 'HH24:MI:SS'), 'HH24:MI:SS') as difference from dual;

Answer 2

Here are few date/timestamp/interval manipulation examples, hope this helps:

SELECT
    TO_DSINTERVAL('0 ' || timeinstring) - NUMTODSINTERVAL(TO_CHAR(timestamp, 'SSSSS'), 'SECOND') RESULT_AS_INTERVAL,
    TRUNC(timestamp) + (TO_DSINTERVAL('0 ' || timeinstring) - NUMTODSINTERVAL(TO_CHAR(timestamp, 'SSSSS'), 'SECOND')) RESULT_AS_DATE,
    TO_CHAR(DATE'1-1-1' + (TO_DSINTERVAL('0 ' || timeinstring) - NUMTODSINTERVAL(TO_CHAR(timestamp, 'SSSSS'), 'SECOND')), 'HH24:MI:SS') RESULT_AS_TIMESTRING
    FROM
        (SELECT TIMESTAMP'2015-12-04 12:34:56' timestamp, '23:34:45' timeInString  FROM DUAL) sample_data;

RESULT_AS_INTERVAL                 RESULT_AS_DATE      RESULT_AS_TIMESTRING
---------------------------------- ------------------- --------------------
+000000000 10:59:49.000000000      04.12.2015 10:59:49 10:59:49