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Good, I have the following 3 tables:
SELECT *
FROM Cartao
INNER JOIN Registo
ON Registo.ID_Cartao=Cartao.ID_Cartao
INNER JOIN Clientes
ON Registo.ID_Cliente=Clientes.ID_Cliente
WHERE Clientes.ID_Cliente=Registo.ID_Cliente
AND Clientes.ID_Cliente=2
With this select I can see the cards that are registered with the client with ID 2. I would like to know which select to view the customer NOT REGISTERED cards with id 2
Thank you
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SELECT *
FROM Cartao
INNER JOIN Registo
ON Registo.ID_Cartao=Cartao.ID_Cartao
INNER JOIN Clientes
ON Registo.ID_Cliente=Clientes.ID_Cliente
WHERE Clientes.ID_Cliente=Registo.ID_Cliente
AND Clientes.ID_Cliente NOT IN (2)
0
According to the numerical set theory applied to the bank, the correct and most performative way to obtain the result would be this:
SELECT *
FROM Cartao
left JOIN Registo
ON Registo.ID_Cartao=Cartao.ID_Cartao
left JOIN Clientes
ON Registo.ID_Cliente=Clientes.ID_Cliente
AND Clientes.ID_Cliente=2
WHERE Clientes.ID_Cliente is null
You will only make a selection using the logic of sets as below:
https://eufacoprogramas.com/wp-content/uploads/2011/05/SQL-Joins-1024x819.jpg
Taking advantage, I did not understand why in Where you put the same condition that used in Join Clientes.ID_Cliente=Registo.ID_Cliente and
Registo.ID_Cliente=Clientes.ID_Cliente
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Note that the condition expressed in the clause WHERE (Clients.Id_client=Registration.Id_client) is the same condition as the junction and therefore totally redundant and unnecessary.
– anonimo