oracle time format query

Oracle is a relational database management system developed and maintained by Oracle Corporation. In Oracle, we often need to query and process time data. Different application scenarios require different time formats, so this article will introduce how to query the time format in Oracle.

Data Type

In Oracle, we can use DATE and TIMESTAMP data types to store date and time data.

The DATE type stores date and time, accurate to seconds. Its format is: YYYY-MM-DD HH24:MI:SS.

TIMESTAMP type has higher precision than DATE and can store nanoseconds after seconds. Its format is: YYYY-MM-DD HH24:MI:SS.FF.

Query the current time

We can use the following statement to query the current time:

SELECT SYSDATE FROM DUAL;

SYSDATE is a function that returns the current time Date and time.

Query the current date

We can use the following statement to query the current date:

SELECT TRUNC(SYSDATE) FROM DUAL;

The TRUNC function intercepts the date, Only the year, month and day parts are retained.

Querying data within a certain time period

Suppose we need to query data within a certain time period, we can use the following statement:

SELECT * FROM table_name
WHERE date_column BETWEEN start_date AND end_date;

Among them, table_name is the name of the table to be queried, date_column is the column name of the date column, start_date and end_date are the start and end dates of the query respectively.

Date formatting

Oracle can use the TO_CHAR function to format dates and times. The following are some commonly used formats:

Format description
YYYY-MM-DD Year-month-day
HH24:MI:SS Hour:minute:second
YYYY-MM-DD HH24:MI:SS Year-month-day hour:minute:second

For example, to Format the date into year-month-day format:

SELECT TO_CHAR(date_column, 'YYYY-MM-DD') FROM table_name;

To format the date into hours:minutes: Second format:

SELECT TO_CHAR(date_column, 'HH24:MI:SS') FROM table_name;

To format the date into year-month-day hour:minute:second format:

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

Query what day of the week a certain day is

We can use the following statement Query what day of the week a certain day is:

SELECT TO_CHAR(date_column, 'DAY') FROM table_name;

DAY will return the English name of the day of the week corresponding to the date.

Summary

In Oracle, we can use DATE and TIMESTAMP data types to store date and time data. To query the current date or time, you can use the SYSDATE function. To format a date or time, you can use the TO_CHAR function. To query data within a certain time period, you can use the BETWEEN keyword. To query what day of the week a certain day is, you can use the TO_CHAR function and DAY format.

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