Using HAVING or WHERE on SUM Fields - sql-server

Question

Problem
We have a Users table and a Addresses table.Each user can have multiple addresses. We have a bit field called IsDefault where a user can select their default address. This field currently isnt mandatory and possibly will be in the future, so I need to do some analysis. Now I want to validate the addresses to see:
How many addresses a given user has.
How many of those addresses (if they have more than 1 address) have
the IsDefault flag set to a 1.
Basically I want to see how many of my users who have multiple addresses, have not switched on any of their addresses to be their default.
I have the following SQL query so far:
SELECT AD.User_Id,
COUNT(AD.User_Id) AS HowManyAddresses,
SUM(
CASE WHEN
AD.IsDefault IS NULL
OR
AD.IsDefault = 0
THEN
1
ELSE
0
END
) AS DefaultEmpty,
SUM(
CASE WHEN
AD.IsDefault = 1
THEN
1
ELSE
0
END
) AS DefaultAddress
FROM dbo.Addresses AS AD
JOIN dbo.Users AS U
ON U.Id = AD.User_Id
GROUP BY AD.User_ID
ORDER BY AD.User_Id
The problem I have found is I want to check the values from the DefaultAddress and DefaultEmpty SELECT SUM fields, but I get the following error when trying to reference them using WHERE or HAVING:
Invalid column name 'DefaultEmpty'.
Is it not possible to reference SUM values for selection purposes?
Technology using:
SQL Server 2008
SQL Server Management Studio 2008

Answer 1

Actually you need to repeat the whole SUM clause with HAVING like this -
SELECT
AD.User_Id
,COUNT(AD.User_Id) AS HowManyAddresses
,SUM(
CASE
WHEN
AD.IsDefault IS NULL OR
AD.IsDefault = 0 THEN 1
ELSE 0
END
) AS DefaultEmpty
,SUM(
CASE
WHEN
AD.IsDefault = 1 THEN 1
ELSE 0
END
) AS DefaultAddress
FROM dbo.Addresses AS AD
JOIN dbo.Users AS U
ON U.Id = AD.User_Id
GROUP BY AD.User_ID
HAVING SUM(
CASE
WHEN
AD.IsDefault IS NULL OR
AD.IsDefault = 0 THEN 1
ELSE 0
END
) = 0
ORDER BY AD.User_Id
OR
DECLARE #address TABLE(UserID INT,Address VARCHAR(100),IsDefault BIT);
INSERT INTO #address VALUES
(1,'User 1 default',1)
,(2,'User 2 non default',0)
,(3,'User 3 non default',0)
,(3,'User 3 default',1)
,(4,'User 4 default',1)
,(4,'User 4 second default',1);
SELECT
COUNT(*) OVER () AS HowManyAddresses
,ISNULL(def0.DefaultEmpty, 0) AS DefaultEmpty
,ISNULL(def1.DefaultAddress, 0) AS DefaultAddress
FROM (SELECT
AD.Address
,COUNT(AD.UserID) OVER (PARTITION BY AD.UserID) AS DefaultEmpty
FROM #address AS AD
WHERE (AD.IsDefault = 0)) def0
FULL JOIN (SELECT
AD.Address
,COUNT(AD.UserID) OVER (PARTITION BY AD.UserID) AS DefaultAddress
FROM #address AS AD
WHERE (AD.IsDefault = 1)) def1
ON def0.Address = def1.Address

Answer 2

You can use CTE in following if you want to use alias names in WHERE clause:
WITH cte AS (
SELECT AD.User_Id,
COUNT(AD.User_Id) AS HowManyAddresses,
SUM(
CASE WHEN
AD.IsDefault IS NULL
OR
AD.IsDefault = 0
THEN
1
ELSE
0
END
) AS DefaultEmpty,
SUM(
CASE WHEN
AD.IsDefault = 1
THEN
1
ELSE
0
END
) AS DefaultAddress
FROM dbo.Addresses AS AD
JOIN dbo.Users AS U
ON U.Id = AD.User_Id
GROUP BY AD.User_ID
ORDER BY AD.User_Id
)
SELECT *
FROM cte
WHERE /* You can use alias names here... */
GROUP BY /* You can use alias names here... */
HAVING /* You can use alias names here... */

Answer 3

This will count - grouped by user and default, how many addresses there are:
DECLARE #user TABLE(ID INT, Name VARCHAR(100));
INSERT INTO #user VALUES
(1,'user1') --will get a default
,(2,'user2') --no default
,(3,'user3') --both
,(4,'user4') --two defaults
,(5,'user5');--nothing
DECLARE #address TABLE(UserID INT,Address VARCHAR(100),IsDefault BIT);
INSERT INTO #address VALUES
(1,'User 1 default',1)
,(2,'User 2 non default',0)
,(3,'User 3 non default',0)
,(3,'User 3 default',1)
,(4,'User 4 default',1)
,(4,'User 4 second default',1);
EDIT: Better with PIVOT...
SELECT p.*
FROM
(
SELECT u.ID,u.Name
,CASE WHEN a.IsDefault=1 THEN 'DEFAULT' ELSE 'NORMAL' END AS PivotColumn
,COUNT(a.UserID) AS CountPerUserAndDefault
FROM #user AS u
LEFT JOIN #address AS a ON u.ID=a.UserID
GROUP BY u.ID,u.Name,a.IsDefault
) AS tbl
PIVOT
(
SUM(CountPerUserAndDefault) FOR PivotColumn IN([DEFAULT],[NORMAL])
) AS p
The result:
Name ID DEFAULT NORMAL
user1 1 1 NULL
user2 2 NULL 1
user3 3 1 1
user4 4 2 NULL
user5 5 NULL 0

Answer 4

Put this after GROUPBY:
HAVING SUM(CAST(AD.IsDefault AS INT)) > 0