SQL Server 2008 : Types of T-SQL Functions

There are rich set of different types built-in T-SQL functions available in SQL Server 2008 which can be broadly categorized as below.

Aggregate functions : Aggregate functions are applied to a group of data values from a column and will always return single value.

• AVG
• COUNT
• COUNT_BIG
• MIN
• MAX
• SUM

Scalare functions: Scalare functions are used in the construction of the scalar expressions and they can be operated on one or more columns. These functions can be further categorized as below.

• Numeric functions
• Date functions
• String functions
• System functions
• Metadata functions

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Reference: DP(http://dptechnicalblog.blogspot.com/ )