MSSQL Statistical Z-Score
Computing the z-score of individual values in SQL Server is not a built in function (although average and standard deviation are). The z-score tells us how far off from the average value the individual values are.
The following function computes the z-score: for a table named [data] having an [objectId] and [score] fields.
The following function computes the z-score: for a table named [data] having an [objectId] and [score] fields.
SELECT [D].[objectId], [D].[score], [E].[avg_score], [E].[stdev_score], ([D].[score] - [E].[avg_score]) / [E].[stdev_score] as zvalue FROM [data] D CROSS JOIN (SELECT Avg(CAST([score] as float)) as [avg_score], StDevP([score]) as [stdev_score] FROM [data] ) E ;
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