The value returned to the caller is always the value at the time the module returns. A parameter is not part of a transaction therefore, if a parameter is changed in a transaction that is later rolled back, the value of the parameter does not revert to its previous value. In Transact-SQL, parameters can be supplied either by using value or by using parameter_name= value. Before you begin Limitations and restrictions Note: Visit user defined function and Create Function (Transact SQL for more information about user defined functions. Select the field to use for sorting (in this case Level1_SortOrder):Īnd that’s how easy it is to use a SQL Window Function! Next time we will cover some other Window functions to demonstrate their power in helping solve data problems.Applies to: SQL Server (all supported versions) Azure SQL DatabaseĮxecute a user defined function using Transact-SQL. Select the Sort by Column functionality in the Modeling tab: Select the field that needs to be sorted: Select the column that needs to be ordered and then choose the sorting column using the Sort by Column functionality on the Modeling tab. Though my usage was in a tabular model, you can also do the same when importing the query into Power BI on the Data panel (as shown below). Now in Power BI, the Level X Sort Order fields can be used to sort the Level X fields.
In this case, Level 1 ends up with 3 distinct values and Level 2 ends up with 6 distinct values, with each level sorted in alphabetical order: The DENSE_RANK() function provides a number for each unique value for the field that its OVER() is applied to. However, the DENSE_RANK() provides the functionality that is needed. The ROW_NUMBER() function will not provide the correct results for this solution’s purposes if applied to the Level 1 or Level 2 fields, as it would provide an individual row number for each value. The ROW_NUMBER() function is used here because it is known that the Territory Name is distinct within the resultset. The OVER(ORDER BY A.) tells the ROW_NUMBER() function to spread the numbers over the resultset using the field. The function call (ROW_NUMBER()) purpose is to provide a distinct number for each row returned in the resultset. SQL #1 – Data is in Leaf level order (Territory ID) and no Window function
#How to execute a function in adventureworks2012 database how to
And yes, we could use the ORDER BY clause to sort alphabetically and be done, but that is not as much fun as learning how to use the ROW_NUMBER and DENSE_RANK Window function! Notice that the ID does not sort the results at the lowest level in an alphabetical fashion, which is what we are going to do to illustrate the SQL Window function. The first SQL statement (SQL #1) returns the data in the order of the Level3 ID, which is the primary key of the table. The hierarchy within the data is as follows: The Sales Territory table and the Country Region table provide the necessary data to illustrate the SQL Window functions of ROW_NUMBER, DENSE_RANK, FIRST, and LAST. Without a sort order for each level of a hierarchy, the results in the report were not properly ordered.Įven though there were (and are) many ways to accomplish this in SQL, I wanted to use SQL Window functions to do the job…Īnd doing so makes for good blog content as well!įor easy accessibility, the examples featured in this article use the Microsoft AdventureWorks database.
During a recent reporting project, I came across a situation in which the solution was to provide the reporting tool ( Power BI sourcing from an SSAS tabular model) a sort order for each level of a dimensional hierarchy.