In this tip, I am going to show you how you can create a Data Access Layer (to store, retrieve and manage data in relational database) in ADO .NET. I will show how you can make it data provider independent, so that you don't have to re-write your data access layer if the data storage source changes and also you can reuse it in other applications that you develop.
2010-06-17
5,532 reads
By Steve Jones
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I have this data in the dbo.Commission table in a SQL Server 2022 database.
salesperson commission Brian 12 Brian 16 Andy 7 Andy 14 Andy 21 Steve 20 Steve NULLAll the data is a varchar, and I decide to run this query to get the totals for each salesperson.
SELECT SalesPerson
, AVG(TRY_PARSE(Commission AS int)) AS TotalCommission
FROM commission
GROUP BY SalesPerson
GO
What average commission is calculated for Steve? See possible answers