Often in SQL Server, you may encounter situations where you need to perform repetitive calculations on a column. While calculated columns can be used to some extent, they are not robust and reusable. In order to reuse code and make calculations more efficient, you can create custom functions in SQL Server. In this article, we will explore how to create and use custom functions in SQL Server.
Solution
For the purpose of this article, let’s consider a scenario where we need to calculate the age of a person from their date of birth. We will create a custom function to perform this calculation.
First, let’s import a sample dataset into SQL Server. This dataset contains two columns – User (name of the user) and DOB (date of birth of the user).
To create the custom function, follow these steps:
- Right-click on the query “Users” and select “Create Function”.
- In the Create Function dialog, provide a name for the function (e.g. “GetAge”) and click OK.
- In the Advanced Editor dialog that appears, enter the formula to calculate the age and click Done.
Now that our custom function is defined, we can use it in our dataset. We will add a new column called “Age” that calculates the age of each user using the custom function.
To add the custom column, follow these steps:
- Click on the table “Users” and select “Custom Column” under the Add Column tab.
- In the Custom Column dialog, provide a name for the new column (e.g. “Age”) and enter the formula “GetAge([DOB])”.
Now you can see that a new column “Age” has been added to the dataset, which calculates the age of each user.
Next Steps
In this article, we have discussed how to create custom functions in SQL Server and use them in a dataset. Custom functions can greatly enhance the efficiency and reusability of your SQL code. To further expand your knowledge, you can explore more about SQL Server functions and their applications.
Thank you for reading!