If you want to be an expert in sql server, then you should learn SQL Server functions. Here, we will guide you and teach you everything about functions in sql server with examples.
What is a Function in SQL Server?
In SQL Server, a function is a pre-written code segment that performs a specific task and returns a value. It’s essentially a set of SQL statements that you can call by name to perform an operation, often with input parameters and returning a result. Functions in SQL Server are broadly classified into two categories:
Types of SQL Server Functions
Built-In Functions
SQL Server provides a vast library of built-in functions. These functions are pre-defined and can be utilized without the need for user-defined code. They are broadly classified into categories such as string functions, mathematical functions, date and time functions, and more. Some key built-in functions include:
- String Functions: Functions like LEN, SUBSTRING, and REPLACE are used for string manipulation.
- Mathematical Functions: Functions such as ROUND, FLOOR, and CEILING assist in mathematical calculations.
- Date and Time Functions: Functions like GETDATE, DATEADD, and DATEDIFF are essential for handling date and time data.
User-Defined Functions
These are functions created by users to meet specific requirements not covered by built-in functions. UDFs can return either a single scalar value or a result set. UDFs can be written in Transact-SQL or CLR languages (like C# or VB.NET). They are especially useful for encapsulating complex logic that can be reused across multiple queries. UDFs can be further classified into:
- Scalar Functions: These return a single value based on the input value.
- Table-Valued Functions: These return a table and can be used like a regular table in SQL queries.
Advantages of Using SQL Server Functions
- Efficiency: Functions reduce the amount of code required, making database queries more efficient.
- Reusability: Functions, especially UDFs, can be reused across multiple SQL queries, saving time and effort.
- Modularity: Breaking down complex logic into functions enhances the readability and maintainability of code.
- Performance: Certain functions can optimize query performance by simplifying complex operations.
SQL Server string functions with examples
Here, check out all the sql server string functions with examples.
| Functions | Descriptions |
|---|---|
| CAST Function in SQL Server | Learn how to convert the datatype of the value to another datatype using the cast() function in sql server. |
| CONVERT Function in SQL Server | This sql server tutorial explains how to alter the datatype of the value to a different datatype using the convert() function. |
| LEFT Function in SQL Server | Learn how to extract the leftmost characters from the string using the LEFT() function in sql server. |
| RIGHT Function in SQL Server | This sql server tutorial explains how to extract the rightmost characters from the string using the RIGHT() function in sql server. |
| LEN Function in SQL Server | This sql server tutorial explains how to find the length of the string using the LEN() function in sql server. |
| Format Function in SQL SERVER | Learn how to format the provided value based on the different format patterns in sql server using the format() function. |
| CHAR Function in SQL Server | This sql server tutorial explains how to get the characters based on the provided integer value using the CHAR() function in sql server. |
| SQL Server RTRIM Function | Learn how to remove the trailing spaces or the other specified characters from the string using the RTRIM() function in sql server. |
| SQL Server LTRIM Function | Learn how to remove the leading spaces or the other specified characters from the string using the LTRIM() function in sql server. |
| SQL Server STR Function | This sql server tutorial explains how to convert the given float number to a character value using the STR() function in sql server. |
| REPLACE Function in SQL Server | This sql server tutorial explains how to substitute a new string in place of the sub-part of the given string using the REPLACE() function in sql server. |
| UPPER Function in SQL Server | Learn how to transform the given string value to uppercase using the UPPER() function in sql server. |
| LOWER Function in SQL Server | Learn how to transform the given string value to lowercase using the LOWER() function in sql server. |
| REPLICATE Function of SQL Server | This sql server tutorial explains how to replicate the given character or string a specified number of times using the REPLICATE() function in sql server. |
| TRY_CONVERT Function in SQL Server | Learn how to convert the value’s data type to another data type using the TRY_CONVERT() function that has error-handling capabilities. |
SQL Server date functions with examples
This section explains how to work with date functions in sql server with examples.
| Functions | Descriptions |
|---|---|
| How to Use CURRENT_TIMESTAMP Function in SQL Server | Learn how to get the current date and time of the system using the CURRENT_TIMESTAMP function in sql server. |
| How to use GETDATE Function in SQL Server | This sql server tutorial explains how to return the current datetime value of the system using the GETDATE() function in sql server. |
| SYSDATETIMEOFFSET Function in SQL Server | Learn how to get the system date and time with timezone offset using the SYSDATETIMEOFFSET() function in sql server. |
| How to use SYSDATETIME Function in SQL Server | This sql server tutorial explains how to retrieve the system’s current date and time with high precision using the SYSDATETIME() function in sql server. |
| SYSUTCDATETIME Function in SQL Server | Learn how to return the system date and time in UTC format using the SYSUTCDATETIME() function in sql server. |
| DATENAME Function of SQL Server | This sql server tutorial explains how to get the specific part of the date, such as year, month, etc using the DATENAME() function in sql server. |
| DATEPART Function in SQL Server | Learn how to extract the specific part ( such as year, month, day, hour, etc) of the date using the DATEPART() function in SQL Server. |
Aggregate functions in SQL Server with examples
Check out all the tutorials on aggregate functions in SQL Server with examples:
| Functions | Descriptions |
|---|---|
| How to use COUNT Function in SQL Server | This sql server tutorial explains the COUNT() aggregate function to count the number of rows in a table. |
| How to use SUM Function in SQL Server | Learn how to compute the sum of all the values in a table column using the SUM() function in sql server. |
| How to use AVG Function in SQL Server | This sql server tutorial explains how to compute the average value of a set of values ( of table column) using the AVG() function in sql server. |
Conclusion
I hope these SQL server function tutorials have helped you to become an expert in SQL Server. Functions are very important in SQL Server.
