Which SQL statement correctly joins the Invoices table with the Clients table on ClientID where ClientID is the primary key in Clients and foreign key in Invoices?
easy📝 Syntax Q3 of 15
SQL - INNER JOIN
Which SQL statement correctly joins the Invoices table with the Clients table on ClientID where ClientID is the primary key in Clients and foreign key in Invoices?
ASELECT * FROM Clients JOIN Invoices ON Clients.InvoiceID = Invoices.ClientID;
BSELECT * FROM Invoices JOIN Clients ON Invoices.ClientID = Clients.ClientID;
CSELECT * FROM Invoices JOIN Clients ON Invoices.InvoiceID = Clients.ClientID;
DSELECT * FROM Clients JOIN Invoices ON Clients.ClientID = Invoices.InvoiceID;
Step-by-Step Solution
Solution:
Step 1: Identify keys
Clients.ClientID is primary key; Invoices.ClientID is foreign key.
Step 2: Match foreign key to primary key
JOIN should be ON Invoices.ClientID = Clients.ClientID.
Final Answer:
SELECT * FROM Invoices JOIN Clients ON Invoices.ClientID = Clients.ClientID; -> Option B
Quick Check:
Foreign key matches primary key in JOIN condition [OK]
Quick Trick:Join foreign key to primary key column [OK]
Common Mistakes:
MISTAKES
Swapping primary and foreign keys in ON clause
Using unrelated columns for JOIN
Confusing InvoiceID with ClientID
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