SQL Functions

Functions in SQL :

Functions are very powerful feature of SQL and can be used to do the followings:

• Perform calculations on data.
• Modify individual data items.
• Manipulate output for group of rows
• Format dates and number for display.
• Convert column data types.

SQL functions sometimes takes arguments and return value. Functions are reusable programs.

Types of SQL Functions:

There are two types of SQL functions they are :

1. Single Row Functions
   • Character function
   • Number function
   • Date function
   • Conversion function
   • General function
2. Multiple Row Functions
   • Group Function

Single Row Functions : 

Single Row Functions are used to

• manipulate data items
• accept arguments and return one value.
• act on each row that is returned.
• it may modify the data type.
• it can be nested.
• it accept arguments that can be a column or expression.

Multiple Row Functions: 

Multiple Row Functions are also called as group function or aggregate functions.