SQL - Insert NULL entry with Union then order by results - sql

Question

Im trying to order a list of results by their description (not id) but i also need to insert another result with a null Id and description of 'ALL'.
To do this I use UNION SELECT NULL, 'ALL'
It should be a pretty simple query but i cant figure out how to insert 'ALL' before the query orders the actual result set.
Here is what I have so far:
SELECT *
FROM [dbo].[HouseType]
WHERE [TypeId] = COALESCE(#TypeId, [TypeId])
UNION SELECT NULL, 'ALL'
ORDER BY [TypeDesc]
Ive also tried calling UNION SELECT before the results are ordered but it doesnt look SQL allows this.
UNION SELECT NULL, 'ALL'
SELECT * FROM
(
SELECT *
FROM [dbo].[HouseType]
WHERE [TypeId] = COALESCE(#TypeId, [TypeId])
ORDER BY [TypeDesc]
)types
Basically I want to see the following results (ordered):
ALL
Bungalow
Detached
Semi-Detached
Terrace

Answer 1

Try using another column:
SELECT t.ID, t.description, 2 AS o
FROM [dbo].[HouseType] AS t
WHERE [TypeId] = COALESCE(#TypeId, [TypeId])
UNION ALL
SELECT NULL, 'ALL', 1 AS o
ORDER BY o, [TypeDesc]
This way ALL will always precede the results of your original query.
Note: As already noted in a comment there must be a match between the number and type of fields of the subqueries used in the UNION operation.
Note 2: As noted in the other comment by #A ツ using UNION ALL is always preferable over UNION, so use this instead when you have no worries about duplicate values.

Answer 2

Try it in a subquery
SELECT *
FROM(
SELECT *
FROM [dbo].[HouseType]
WHERE [TypeId] = COALESCE(#TypeId, [TypeId])
UNION
SELECT NULL, 'ALL')
ORDER BY [TypeDesc]

Answer 3

DECLARE #HouseType TABLE (HouseType VARCHAR(30))
INSERT INTO #HouseType
SELECT HouseType
FROM [dbo].[HouseType]
WHERE [TypeId] = COALESCE(#TypeId, [TypeId])
ORDER BY [TypeDesc]
INSERT INTO #HouseType
SELECT 'ALL'
SELECT HouseType FROM #HouseType ORDER BY HouseType

Answer 4

I think you are looking for conditional sorting:
SELECT *
FROM [dbo].[HouseType]
WHERE [TypeId] = COALESCE(#TypeId, [TypeId])
UNION ALL
SELECT NULL, 'ALL'
ORDER BY CASE WHEN [TypeDesc] = 'ALL' THEN 0 ELSE 1 END, [TypeDesc]
btw, I would suggest agains the use of * and explicitly specify the column names in the select list.
This is always best practice, espcially when using UNION - this query will raise an error if you ever add (or remove) a column from the HouseType table.

Answer 5

Assigns a Row to each TypeDesc using ROW_NUMBER function (+1 to go after the 'ALL') sorted by TypeDesc:
select 1 as [Row], 'All' as [TypeDesc]
union
SELECT ROW_NUMBER() OVER (ORDER BY TypeDesc) + 1 AS [Row], [TypeDesc]
FROM [dbo].[HouseType]
WHERE [TypeId] = COALESCE(#TypeId, [TypeId])
ORDER BY [Row]