Home Database Oracle oracle conversion time format

oracle conversion time format

May 14, 2023 am 09:40 AM

In Oracle database, the timestamp data type can represent any date and time. However, its default format may not meet our needs, so time format conversion is required. This article will introduce how to use conversion functions to implement time format conversion in Oracle database.

  1. TO_CHAR function

The TO_CHAR function can format a date type column or value into a specified string format. Among them, the first parameter is a value or column of date type, and the second parameter is a character expression in the date/time format to be converted. Commonly used date/time formats include the following:

  • YYYY four-digit year, for example: 2022.
  • MM Two-digit month, padded with leading zeros, for example: 04.
  • DD Two-digit date, padded with leading zeros, for example: 30.
  • hh Two-digit hour, padded with leading zeros, for example: 08.
  • mi Two-digit minute, padded with leading zeros, for example: 45.
  • ss Two-digit number of seconds, padded with leading zeros, for example: 12.

For example, to format the current time into the format of "YYYY-MM-DD hh:mi:ss", you can use the following SQL statement:

SELECT TO_CHAR(SYSDATE, 'YYYY-MM-DD hh24:mi:ss') FROM DUAL;
Copy after login

Among them, SYSDATE is The current system time, DUAL is an Oracle predefined table, which contains only one row and one column. It is often used to test single-column return value functions.

  1. TO_DATE function

The TO_DATE function can convert a character expression into a date type value. Among them, the first parameter is the string to be converted, and the second parameter is the character expression in the date/time format of the string. Commonly used date/time formats are consistent with those in the TO_CHAR function.

For example, to convert the string "2022-04-30 08:45:12" into a DATE type value, you can use the following SQL statement:

SELECT TO_DATE('2022-04-30 08:45:12', 'YYYY-MM-DD hh24:mi:ss') FROM DUAL;
Copy after login
  1. CAST function

The CAST function can convert one data type to another data type, including date/time type conversion. For example, to convert a DATE type value to a TIMESTAMP type, you can use the following SQL statement:

SELECT CAST(SYSDATE AS TIMESTAMP) FROM DUAL;
Copy after login
  1. EXTRACT function

The EXTRACT function can convert a date/time type value from Extract specified parts, such as year, month, day, hour, minute, second, etc. Among them, the first parameter is the extracted part, and the second parameter is a date/time type value.

For example, to extract the year and month from the current time, you can use the following SQL statement:

SELECT EXTRACT(YEAR FROM SYSDATE), EXTRACT(MONTH FROM SYSDATE) FROM DUAL;
Copy after login

The above are several common methods and functions for time format conversion in Oracle database, different Scenarios may require the use of different methods and functions for conversion, which need to be selected based on actual needs.

The above is the detailed content of oracle conversion time format. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

What are the oracle database operation tools? What are the oracle database operation tools? Apr 11, 2025 pm 03:09 PM

In addition to SQL*Plus, there are tools for operating Oracle databases: SQL Developer: free tools, interface friendly, and support graphical operations and debugging. Toad: Business tools, feature-rich, excellent in database management and tuning. PL/SQL Developer: Powerful tools for PL/SQL development, code editing and debugging. Dbeaver: Free open source tool, supports multiple databases, and has a simple interface.

How to check tablespace size of oracle How to check tablespace size of oracle Apr 11, 2025 pm 08:15 PM

To query the Oracle tablespace size, follow the following steps: Determine the tablespace name by running the query: SELECT tablespace_name FROM dba_tablespaces; Query the tablespace size by running the query: SELECT sum(bytes) AS total_size, sum(bytes_free) AS available_space, sum(bytes) - sum(bytes_free) AS used_space FROM dba_data_files WHERE tablespace_

Oracle PL/SQL Deep Dive: Mastering Procedures, Functions & Packages Oracle PL/SQL Deep Dive: Mastering Procedures, Functions & Packages Apr 03, 2025 am 12:03 AM

The procedures, functions and packages in OraclePL/SQL are used to perform operations, return values ​​and organize code, respectively. 1. The process is used to perform operations such as outputting greetings. 2. The function is used to calculate and return a value, such as calculating the sum of two numbers. 3. Packages are used to organize relevant elements and improve the modularity and maintainability of the code, such as packages that manage inventory.

Oracle GoldenGate: Real-Time Data Replication & Integration Oracle GoldenGate: Real-Time Data Replication & Integration Apr 04, 2025 am 12:12 AM

OracleGoldenGate enables real-time data replication and integration by capturing the transaction logs of the source database and applying changes to the target database. 1) Capture changes: Read the transaction log of the source database and convert it to a Trail file. 2) Transmission changes: Transmission to the target system over the network, and transmission is managed using a data pump process. 3) Application changes: On the target system, the copy process reads the Trail file and applies changes to ensure data consistency.

How to create oracle database How to create oracle database How to create oracle database How to create oracle database Apr 11, 2025 pm 02:36 PM

To create an Oracle database, the common method is to use the dbca graphical tool. The steps are as follows: 1. Use the dbca tool to set the dbName to specify the database name; 2. Set sysPassword and systemPassword to strong passwords; 3. Set characterSet and nationalCharacterSet to AL32UTF8; 4. Set memorySize and tablespaceSize to adjust according to actual needs; 5. Specify the logFile path. Advanced methods are created manually using SQL commands, but are more complex and prone to errors. Pay attention to password strength, character set selection, tablespace size and memory

How to get time in oracle How to get time in oracle Apr 11, 2025 pm 08:09 PM

There are the following methods to get time in Oracle: CURRENT_TIMESTAMP: Returns the current system time, accurate to seconds. SYSTIMESTAMP: More accurate than CURRENT_TIMESTAMP, to nanoseconds. SYSDATE: Returns the current system date, excluding the time part. TO_CHAR(SYSDATE, 'YYY-MM-DD HH24:MI:SS'): Converts the current system date and time to a specific format. EXTRACT: Extracts a specific part from a time value, such as a year, month, or hour.

How to view instance name of oracle How to view instance name of oracle Apr 11, 2025 pm 08:18 PM

There are three ways to view instance names in Oracle: use the "sqlplus" and "select instance_name from v$instance;" commands on the command line. Use the "show instance_name;" command in SQL*Plus. Check environment variables (ORACLE_SID on Linux) through the operating system's Task Manager, Oracle Enterprise Manager, or through the operating system.

How to learn oracle database How to learn oracle database Apr 11, 2025 pm 02:54 PM

There are no shortcuts to learning Oracle databases. You need to understand database concepts, master SQL skills, and continuously improve through practice. First of all, we need to understand the storage and management mechanism of the database, master the basic concepts such as tables, rows, and columns, and constraints such as primary keys and foreign keys. Then, through practice, install the Oracle database, start practicing with simple SELECT statements, and gradually master various SQL statements and syntax. After that, you can learn advanced features such as PL/SQL, optimize SQL statements, and design an efficient database architecture to improve database efficiency and security.

See all articles