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Statistics in SQL: Kendall’s Tau rank correlation

Statistical calculations in SQL are often perfectly easy to do. SQL was designed to be a natural fit for calculating correlation, regression and variance on large quantities of data. It just isn't always immediately obvious how. In the second of a series of articles, Phil factor shows how calculating a non-parametric correlation via Kendall's Tau or Spearman's Rho can be stress-free.

2017-06-20

3,513 reads

External Article

Questions About SQL Server Collations You Were Too Shy to Ask

Of course we all like our colleagues to think that we know everything there is to know about SQL Server Collations. However, the truth is that it is a rather complicated topic to fully understand and the cost of getting collation wrong can be great. If only one could ask certain questions on forums or at conferences without blushing. Help is at hand, because Robert Sheldon once again makes the complicated seem simple by answering those questions that you were too shy to ask.

2017-06-15

3,969 reads

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The Empty Aggregate

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Question of the Day

The Empty Aggregate

I have this table in a SQL Server 2025 database:

CREATE TABLE [dbo].[CustomerOrder]
(
[OrderID] [int] NULL,
[CustomerID] [int] NULL,
[total] [money] NULL
) ON [PRIMARY]
GO
What is returned from this code? (answers are for the sum and then the count)
SELECT SUM(total) AS sum,
       COUNT(total) AS count
FROM dbo.CustomerOrder;



See possible answers