Which SQL query correctly lists all customers who have orders in 2023 using a join?

Which SQL query correctly lists all customers who have orders in 2023 using a join?

• A. SELECT c.* FROM Customers c, Orders o ON c.CustomerID = o.CustomerID WHERE YEAR(o.OrderDate) = 2023;
• B. SELECT c.* FROM Customers c INNER JOIN Orders o ON c.CustomerID = o.CustomerID WHERE YEAR(o.OrderDate) = 2023;
• C. SELECT c.* FROM Customers c INNER JOIN Orders o ON c.CustomerID = o.CustomerID;
• D. SELECT c.* FROM Customers c INNER JOIN Orders o ON c.CustomerID = o.CustomerID WHERE YEAR(o.OrderDate) = 2024;

Answer: (B)

Joining tables with an inner join and filtering by the date is what picks out customers who have orders in a specific year. The right approach connects Customers and Orders on their common CustomerID, then narrows the results to orders whose date falls in 2023. This ensures you only see customers who actually placed an order during that year. Using an explicit INNER JOIN with an ON clause is important because it clearly defines how the two tables relate. The other styles either try to mix a comma-style join with ON (which isn’t valid syntax for joining with a condition), omit the year filter entirely (so you’d get customers with orders in any year), or filter for a different year altogether. If you need only unique customers, you can add DISTINCT to avoid duplicates when a customer has multiple orders in 2023.

Joining tables with an inner join and filtering by the date is what picks out customers who have orders in a specific year. The right approach connects Customers and Orders on their common CustomerID, then narrows the results to orders whose date falls in 2023. This ensures you only see customers who actually placed an order during that year.

Using an explicit INNER JOIN with an ON clause is important because it clearly defines how the two tables relate. The other styles either try to mix a comma-style join with ON (which isn’t valid syntax for joining with a condition), omit the year filter entirely (so you’d get customers with orders in any year), or filter for a different year altogether. If you need only unique customers, you can add DISTINCT to avoid duplicates when a customer has multiple orders in 2023.