AVG() not accurate in SQL Server

问题

I am trying to calculate an Avg() for an column with where condition using SQL Server Management Studio 2008. When I try the AVG(column-name) in a SQL query it gives me a rounded value and not a decimal value.

When I copy the dataset into MS Excel I get the accurate value with 4 decimal (example: 10.74) in SQL I am getting just 10. Any help is appreciated.

My query:

SELECT Item, AVG(POOrdrQty) 
FROM [tableWR] 
where Item ='737' AND POOrdrQty <((select AVG([POOrdrQty]) FROM [tableWR]) * 2) 
group by Item

回答1:

The resulting type of the avg aggregate is the same type as the value you use as parameter. If the field is an int, the result will be rounded to fit the type.

Cast the value that you use as parameter: avg(cast(column-name as float)).

来源：https://stackoverflow.com/questions/18493976/avg-not-accurate-in-sql-server