How to find the average value in a column of dates in SQL Server

Question

I have a table of 5000 records with a date column.

How do I find the average of those dates. I\'ve tried AVG(datefield), but it says Operand da

Answer 1

CONVERT(DATETIME, AVG(CONVERT(FLOAT, datefield))) as [AverageDate] 

Answer 2

For those of you getting a conversion error (can't convert date to int or float)... Here's a simple solution using datediff and dateadd

SELECT 
DATEADD(DAY, AVG(DATEDIFF(DAY, '1900-01-01', datefield)), '1900-01-01') AS [AverageDate]
FROM dates;

Note that the January 1st 1900 date is arbitrary, it just has to be the same in both spots.

Answer 3

If you want to average date only:

SELECT CAST(AVG(CAST(datefield AS INT)) AS DATETIME) FROM dates;

And if you want to consider time:

SELECT CAST(AVG(CAST(datefield AS FLOAT)) AS DATETIME) FROM dates;

See fiddle to test.