Today's question (by Greg Larsen):

Inlining Scalar UDFs

--Function 1
CREATE OR ALTER FUNCTION dbo.GetRating_1(@CustomerID INT) 
RETURNS VARCHAR(20) 
AS 
BEGIN 
DECLARE @Rating VARCHAR(20);
SELECT @Rating = Rating 
FROM Customer 
WHERE CustomerID = @CustomerID;

RETURN @Rating;
END
GO

CREATE OR ALTER FUNCTION dbo.GetRating_2(@CustomerID INT) 
RETURNS VARCHAR(20) 
AS 
BEGIN 
DECLARE @Rating varchar(20);
IF @CustomerID % 4 = 0 BEGIN 
SET @Rating = 'Diamond';
END
ELSE IF @CustomerID % 4 = 1 BEGIN
SET @Rating = 'Gold';
END
ELSE IF @CustomerID % 4 = 2 BEGIN 
SET @Rating = 'Silver';
END
ELSE IF @CustomerID % 4 = 3 BEGIN 
SET @Rating = 'Bronze';
END

RETURN @Rating;
END

GO

--Function 3
CREATE OR ALTER FUNCTION dbo.GetRating_3(@CustomerID INT) 
RETURNS VARCHAR(20) 
AS 
BEGIN 
DECLARE @Rating varchar(20);
DECLARE @RatingID INT;

SELECT @RatingID = RatingID 
FROM Customer
WHERE CustomerID = @CustomerID;

IF @RatingID = 0 BEGIN 
SET @Rating = 'Diamond';
END
ELSE IF @RatingID = 1 BEGIN
SET @Rating = 'Gold';
END
ELSE IF @RatingID = 2 BEGIN 
SET @Rating = 'Silver';
END
ELSE IF @RatingID = 3 BEGIN 
SET @Rating = 'Bronze';
END

RETURN @Rating;
END


GO

--Function 4
CREATE OR ALTER FUNCTION dbo.GetRating_4(@CustomerID INT)
RETURNS VARCHAR(20)
AS
BEGIN
   DECLARE @Ratings TABLE(RatingID INT, RatingDesc  varchar(20));
   DECLARE @Rating VARCHAR(20);

   INSERT INTO @Ratings(RatingID, RatingDesc)
   SELECT RatingID, RatingDesc
   FROM Rating;

   SELECT @Rating = R.RatingDesc
   FROM Customer  AS C
   JOIN @Ratings  AS R ON C.RatingID = R.RatingID
   WHERE CustomerID = @CustomerID;

   RETURN @Rating;

END

GO

--Function 5
CREATE OR ALTER FUNCTION dbo.GetRating_5(@RatingID INT) 
RETURNS VARCHAR(20) 
AS 
BEGIN 

DECLARE @ID INT = 0;
DECLARE @Rating varchar(20);

WHILE @ID <> @RatingID BEGIN 
SET @ID = @ID + 1;
END;

SELECT @Rating = RatingDesc 
FROM Rating 
WHERE RatingID = @ID;

RETURN @Rating;
END

Think you know the answer? Click here, and find out if you are right.

A chart of costs in R

I have this dataframe in R:

> head(sales)
        Date Day    Month Year Customer_Age      Age_Group Customer_Gender
1 2013-11-26  26 November 2013           19    Youth (<25)               M
2 2015-11-26  26 November 2015           19    Youth (<25)               M
3 2014-03-23  23    March 2014           49 Adults (35-64)               M
4 2016-03-23  23    March 2016           49 Adults (35-64)               M
5 2014-05-15  15      May 2014           47 Adults (35-64)               F
6 2016-05-15  15      May 2016           47 Adults (35-64)               F

I am looking to get this histogram of unit costs:

What should I run to get this?

Answer: hist(sales$Unit_Cost)

Explanation: A quick histogram is from the hist() function. Ref: hist() - https://www.datamentor.io/r-programming/histogram/

Discuss this question and answer on the forums

Here's a few of the new posts today on the forums. To see more, visit the forums.