How to query oracle time format

There are many different time formats in Oracle database that can be used to store and display date and time information. The correct time format is very important when querying and analyzing data. This article will introduce how to query the date and time format in the Oracle database, and how to output the date and time data into the specified format.

Oracle date format

The date formats supported by Oracle database include:

1. Year-month-day (YYYY-MM-DD)
2. Month/Day/Year(MM/DD/YYYY)
3. Day.Month.Year(DD.MM.YYYY)
4. 日月年(DDMMYYYY)
5. Year Month Day, hour, minute, and second (YYYY-MM-DD HH24:MI:SS)
6. Year, month, day, hour, minute, and second millisecond (YYYY-MM-DD HH24:MI:SS.FF)
7. Hour, minute, and second ( HH24:MI:SS)

In Oracle, date data is stored in a 7-byte numeric format. The first 3 bytes store the year, the middle two bytes store the month, and the last two bytes store the date. Time data is stored in the fractional part, measured in thousandths of a second.

Query Oracle date format

To query the date format in the Oracle database, you can use the TO_CHAR function to convert date data into a string:

SELECT TO_CHAR(sysdate, 'YYYY -MM-DD HH24:MI:SS') FROM dual;

In this query, we use the sysdate function to get the current system date and time, and use the TO_CHAR function to convert it to the specified date format (i.e. Year, month, day, hour, minute and second format).

Output Oracle date format

In Oracle, you can use the TO_CHAR function to output date and time data as a string in the specified format. The following are some common date and time output formats:

1. Year, month, day: YYYY-MM-DD
2. Year, month, day, hour and minute: YYYY-MM-DD HH24:MI
3. Year, month, day, hour, minute and second: YYYY-MM-DD HH24:MI:SS
4. Year, month, day, hour, minute, second and millisecond: YYYY-MM-DD HH24:MI:SS.FF
5. Hours, minutes and seconds: HH24:MI:SS

For example, the following query will output the order creation date in year, month and day format:

SELECT TO_CHAR(order_date, 'YYYY-MM-DD ') FROM orders;

In this query, we use the TO_CHAR function to convert the order creation date into the specified format (i.e. year, month, day format).

Summary

Querying and processing date and time data is very important in Oracle database. The correct time format helps us analyze and use the data correctly. Oracle supports multiple date and time formats, which can be selected as needed, and use the TO_CHAR function to output date and time data as strings in the specified format. When querying and analyzing time data, be sure to double-check and confirm the date format used to ensure correctness and accuracy.

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