First of all create a table which have value RatingID and your content id like in my logic SiteID like Comments then create a stored procedure like

CREATE PROCEDURE Q_GetRatingInfo(@SiteID int) AS

SELECT

(SELECT COUNT(*) FROM Comments WHERE SiteID = @SiteID AND RatingID = 1) as Rating1Count,

(SELECT COUNT(*) FROM Comments WHERE SiteID = @SiteID AND RatingID = 2) as Rating2Count,

(SELECT COUNT(*) FROM Comments WHERE SiteID = @SiteID AND RatingID = 3) as Rating3Count,

(SELECT COUNT(*) FROM Comments WHERE SiteID = @SiteID AND RatingID = 4) as Rating4Count,

(SELECT COUNT(*) FROM Comments WHERE SiteID = @SiteID AND RatingID = 5) as Rating5Count,

ISNULL((SELECT AVG(CONVERT(float, RatingID)) FROM Comments WHERE SiteID = @SiteID), 0.0) as AvgRating,

(SELECT COUNT(*) FROM Comments WHERE SiteID = @SiteID) as RatingCount

GO



then create a function AvgRating

Public Function AvgRating(ByVal SiteID As Integer) As Decimal

Dim con As New SqlConnection(myConStr)
con.Open()

Dim avgrate As Decimal

Dim myCommand As SqlCommandmyCommand = New SqlCommand("Q_GetRatingInfo", con)
myCommand.CommandType = CommandType.StoredProcedure

myCommand.Parameters.AddWithValue("@SiteID", SiteID)

Dim reader As SqlDataReader = myCommand.ExecuteReader(CommandBehavior.CloseConnection)
If reader.Read Then

avgrate = Convert.ToSingle(reader("AvgRating"))
End If

con.Close()

Return avgrate
End Function

User Rating Technique