• Skip to main content
  • Skip to primary sidebar
  • Skip to secondary sidebar
  • Skip to footer

Computer Notes

Library
    • Computer Fundamental
    • Computer Memory
    • DBMS Tutorial
    • Operating System
    • Computer Networking
    • C Programming
    • C++ Programming
    • Java Programming
    • C# Programming
    • SQL Tutorial
    • Management Tutorial
    • Computer Graphics
    • Compiler Design
    • Style Sheet
    • JavaScript Tutorial
    • Html Tutorial
    • Wordpress Tutorial
    • Python Tutorial
    • PHP Tutorial
    • JSP Tutorial
    • AngularJS Tutorial
    • Data Structures
    • E Commerce Tutorial
    • Visual Basic
    • Structs2 Tutorial
    • Digital Electronics
    • Internet Terms
    • Servlet Tutorial
    • Software Engineering
    • Interviews Questions
    • Basic Terms
    • Troubleshooting
Menu

Header Right

Home » Sql » Functions » SQL CAST() Function
Next →
← Prev

SQL CAST() Function

By Dinesh Thakur

All of the aforementioned functions relate to specific ways to manipulate character, date/time, or numeric datatypes. But you may need to convert data from one datatype to another or convert NULL values to something meaningful.

The CAST function allows you to convert data from one datatype to another. The general format of the function is:

CAST (Expression AS DataType) 

The CAST function is actually unnecessary in many situations. Let’s take the situation where you want to execute this statement, where the Quantity column is defined as a character column:

SELECT 2 * Quantity FROM table; 

You might think that the statement would fail due to the fact that Quantity is not defined as a numeric column. However, most SQL databases are smart enough to automatically convert the Quantity column to a numeric value so it can be multiplied by 2.

Here’s an example where you may need to use the CAST function. Let’s say that you have a column with dates stored in a character column. You would like to convert those dates to a true date/time column. This statement illustrates how the CAST function can handle that conversion:

SELECT'2009-04-11' AS 'Original Date', CAST ('2009-04-11' AS DATETIME) AS 'Converted Date'FROM DUAL; 

The output is:

Original Date         Converted Date

2009-04-11          2009-04-11 00:00:00

The Original Date column looks like a date, but it is really just character data. In contrast, the Converted Date column is a true date/time column, as evidenced by the time value, which is now shown.

The equivalent statement for the previous CAST function in Oracle is:

SELECT'2009-04-11' AS "Original Date", CAST ('2009-04-11' AS DATETIME) AS "Converted Date"FROM DUAL; 

 

You’ll also like:

  1. SQL NVL Function
  2. SQL: DECODE Function
  3. SQL DATEPART() Function
  4. SQL GETDATE() Function
  5. SQL: COUNT Function
Next →
← Prev
Like/Subscribe us for latest updates     

About Dinesh Thakur
Dinesh ThakurDinesh Thakur holds an B.C.A, MCDBA, MCSD certifications. Dinesh authors the hugely popular Computer Notes blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps.

Dinesh Thakur is a Freelance Writer who helps different clients from all over the globe. Dinesh has written over 500+ blogs, 30+ eBooks, and 10000+ Posts for all types of clients.


For any type of query or something that you think is missing, please feel free to Contact us.


Primary Sidebar

SQL Tutorials

SQL Tutorials

  • SQL - Home
  • SQL - Select
  • SQL - Create
  • SQL - View
  • SQL - Sub Queries
  • SQL - Update
  • SQL - Delete
  • SQL - Order By
  • SQL - Select Distinct
  • SQL - Group By
  • SQL - Where Clause
  • SQL - Select Into
  • SQL - Insert Into
  • SQL - Sequence
  • SQL - Constraints
  • SQL - Alter
  • SQL - Date
  • SQL - Foreign Key
  • SQL - Like Operator
  • SQL - CHECK Constraint
  • SQL - Exists Operator
  • SQL - Drop Table
  • SQL - Alias Syntax
  • SQL - Primary Key
  • SQL - Not Null
  • SQL - Union Operator
  • SQL - Unique Constraint
  • SQL - Between Operator
  • SQL - Having Clause
  • SQL - Isnull() Function
  • SQL - IN Operator
  • SQL - Default Constraint
  • SQL - Minus Operator
  • SQL - Intersect Operator
  • SQL - Triggers
  • SQL - Cursors

Advanced SQL

  • SQL - Joins
  • SQL - Index
  • SQL - Self Join
  • SQL - Outer Join
  • SQL - Join Types
  • SQL - Cross Join
  • SQL - Left Outer Join
  • SQL - Right Join
  • SQL - Drop Index
  • SQL - Inner Join
  • SQL - Datediff() Function
  • SQL - NVL Function
  • SQL - Decode Function
  • SQL - Datepart() Function
  • SQL - Count Function
  • SQL - Getdate() Function
  • SQL - Cast() Function
  • SQL - Round() Function

Other Links

  • SQL - PDF Version

Footer

Basic Course

  • Computer Fundamental
  • Computer Networking
  • Operating System
  • Database System
  • Computer Graphics
  • Management System
  • Software Engineering
  • Digital Electronics
  • Electronic Commerce
  • Compiler Design
  • Troubleshooting

Programming

  • Java Programming
  • Structured Query (SQL)
  • C Programming
  • C++ Programming
  • Visual Basic
  • Data Structures
  • Struts 2
  • Java Servlet
  • C# Programming
  • Basic Terms
  • Interviews

World Wide Web

  • Internet
  • Java Script
  • HTML Language
  • Cascading Style Sheet
  • Java Server Pages
  • Wordpress
  • PHP
  • Python Tutorial
  • AngularJS
  • Troubleshooting

 About Us |  Contact Us |  FAQ

Dinesh Thakur is a Technology Columinist and founder of Computer Notes.

Copyright © 2025. All Rights Reserved.

APPLY FOR ONLINE JOB IN BIGGEST CRYPTO COMPANIES
APPLY NOW