Date Conversion in Oracle

There are many date conversion functions in Oracle, and the common commands are as follows:

• The To_char () command converts a timestamp to a user-specified date format, such as:

SELECT to_char (sysdate, ' Yyyy-mm-dd hh24:mi:ss ') from DUAL;

Syntax: To_char (X [, format])

Description: Converts x into a string by format. X can be a date or a number or a timestamp, format is a formatted string that specifies what format to convert x

• The to_date () command converts a string of date formats to date type data, such as:

SELECT to_date (' 2014-05-07 13:23:44 ', ' yyyy-mm-dd hh24:mi:ss ') from DUAL;

Syntax: To_date (C [, format])

Description: Converts a string C that conforms to a specific date format specified by format to a date type of data

• The To_timestamp () function converts a time-formatted string to a timestamp

SELECT to_timestamp (' 2014-06-20 12:11:11 ', ' yyyy-mm-dd HH24:MI:SS ') from dual;

Syntax: To_timestamp (C [, format])

Description: Converts a string C to a timestamp data type

The---to_char () command converts a timestamp to a string:
Select To_char (To_timestamp (' 2014-06-20 12:11:11 ', ' yyyy-mm-dd HH24:MI:SS '), ' Yyyy-mm-dd HH24:MI:SS ') from dual;

• When a comparison of two dates is required, no comparison time is required, and the date can be intercepted using the trunc () command

Sql> Select To_char (trunc (sysdate), ' Yyyy-mm-dd HH24:MI:SS ') from dual;
Sql> Select To_char (sysdate, ' Yyyy-mm-dd HH24:MI:SS ') from dual;

Date Conversion in Oracle