How to get data from multiple tables using SQL query - sql

Question

I have three Tables Administration with relation one-to-many with Telephone, Fax Tables:
Administration : Id_Administration, Lib_Administration
Telephone: Id_Phone, Phone_Number, Id_Administration
Fax: Id_Fax, Fax_Number, Id_Administration
Administration table contains:
Id_Administration Lib_Administration
1 adminstration1
2 adminstration2
Telephone table contains:
Id_Phone Phone_Number Id_Administration
1 0313131 1
2 0212121 1
3 0353535 2
4 0343434 2
Fax table contains:
Id_Fax Fax_Number Id_Administration
1 0323232 1
2 0363636 2
3 0373737 2
I want to make a query to show this result:
Id_Administration Lib_Administration Phone_Number Fax_Number
1 adminstration1 0313131 0323232
0212121
2 adminstration2 0353535 0363636
0343434 0373737
I used this query
SELECT Administration.Id_Administration, Administration.Lib_Administration,Telephone.Phone_Number, Fax.Fax_Number
FROM ((Administration INNER JOIN
Telephone ON Administration.Id_Administration = Telephone.Id_Administration) INNER JOIN
Fax ON Administration.Id_Administration = Fax.Id_Administration)
But the result was iterated like this:
Id_Administration Lib_Administration Phone_Number Fax_Number
1 adminstration1 0313131 0323232
0212121 0323232
2 adminstration2 0353535 0363636
0343434 0363636
0353535 0373737
0343434 0373737
I used left join but i didn't get the right result, so where is the problem in my query?

Answer 1

Everything is possible, but sometimes hard work to achieve our goal is not worth it. Are you trying to prepare a recordset for your form?
In this scenario I would have 2 subforms, for phone and fax numbers. No need to load all in one recordset.

Answer 2

I don't think the original table structure works. In the posted DDL you have administration-level granularity. What you want to do is pair a phone number with a fax number- I would call this the office-level granularity. What you can do is add another level of granularity by creating an Office table. In the inserts, link each phone and fax number also to this office ID. For the Select, join the phone and fax tables also to this Id_Office. This should pair the phones by both Organization and Office to give the expected output.
For example if you include an Office table similar to below:
CREATE TABLE Administration (Id_Administration int, Lib_Administration varchar(100))
INSERT INTO Administration (Id_Administration, Lib_Administration) VALUES
(1, 'adminstration1'), (2, 'adminstration2')
CREATE TABLE Office(Id_Administration int, Id_Office int, Lib_Office varchar(100))
INSERT INTO Office (Id_Administration, Id_Office, Lib_Office) VALUES
(1, 1, 'A1 Office 1'), (1, 2, 'A1 Office 2')
,(2, 1, 'A2 Office 2'), (2, 2, 'A2 Office 2')
CREATE TABLE Fax (Id_Fax int, Fax_Number char(7), Id_Administration int, Id_Office int)
INSERT INTO Fax (Id_Fax, Fax_Number, Id_Administration, Id_Office) VALUES
(1, '0323232', 1, 1), (2, '0363636', 2, 1)
,(3, '0373737', 2, 2)
CREATE TABLE Telephone (Id_Phone int, Phone_Number char(7), Id_Administration int, Id_Office int)
INSERT INTO Telephone (Id_Phone, Phone_Number, Id_Administration, Id_Office) VALUES
(1, '0313131', 1, 1)
,(2, '0212121', 1, 2)
,(3, '0353535', 2, 1)
,(4, '0343434', 2, 2)
SELECT A.Id_Administration, A.Lib_Administration, T.Phone_Number, COALESCE(F.Fax_Number, '') AS Fax_Number
FROM Administration A LEFT JOIN Office O ON A.Id_Administration = O.Id_Administration
LEFT JOIN Fax F ON F.Id_Administration = A.Id_Administration AND F.Id_Office = O.Id_Office
LEFT JOIN Telephone T ON T.Id_Administration = A.Id_Administration AND T.Id_Office = O.Id_Office
This produces output:
Id_Administration Lib_Administration Phone_Number Fax_Number
1 adminstration1 0313131 0323232
1 adminstration1 0212121
2 adminstration2 0353535 0363636
2 adminstration2 0343434 0373737
http://sqlfiddle.com/#!18/27964/3/0