Solution:Step 1: Understand requirement - total per customer with orders onlyINNER JOIN keeps only customers with matching orders; GROUP BY customer name to sum amounts.Step 2: Check query correctnessSELECT c.Name, SUM(o.Amount) FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID GRO

[Solved] You have two tables:OrdersOrderID | CustomerID | Amount1 | 101 | 502 | 102 | 753 | 103 | 1004 | 101 | 25CustomersCustomerID | Name101 | John102 | Jane104 | MikeWrite an INNER JOIN query to find total... | SQL

SQL - INNER JOIN

You have two tables:

Orders
OrderID | CustomerID | Amount
1 | 101 | 50
2 | 102 | 75
3 | 103 | 100
4 | 101 | 25

Customers
CustomerID | Name
101 | John
102 | Jane
104 | Mike

Write an INNER JOIN query to find total order amount per customer name, including only customers with orders. Which query is correct?

ASELECT c.Name, SUM(o.Amount) FROM Customers c INNER JOIN Orders o ON c.CustomerID = o.CustomerID GROUP BY c.CustomerID;

BSELECT c.Name, SUM(o.Amount) FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID GROUP BY c.Name;

CSELECT c.Name, SUM(o.Amount) FROM Customers c LEFT JOIN Orders o ON c.CustomerID = o.CustomerID GROUP BY c.Name;

DSELECT c.Name, SUM(o.Amount) FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID GROUP BY o.CustomerID;

Step-by-Step Solution

Solution:

Step 1: Understand requirement - total per customer with orders only
INNER JOIN keeps only customers with matching orders; GROUP BY customer name to sum amounts.
Step 2: Check query correctness
SELECT c.Name, SUM(o.Amount) FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID GROUP BY c.Name; joins Orders to Customers on CustomerID and groups by c.Name, matching requirement exactly.
Step 3: Compare other options
SELECT c.Name, SUM(o.Amount) FROM Customers c INNER JOIN Orders o ON c.CustomerID = o.CustomerID GROUP BY c.CustomerID; groups by CustomerID but c.Name not grouped (SQL error). SELECT c.Name, SUM(o.Amount) FROM Customers c LEFT JOIN Orders o ON c.CustomerID = o.CustomerID GROUP BY c.Name; uses LEFT JOIN (includes customers without orders). SELECT c.Name, SUM(o.Amount) FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID GROUP BY o.CustomerID; groups by o.CustomerID (not customer name).
Final Answer:
SELECT c.Name, SUM(o.Amount) FROM Orders o INNER JOIN Customers c ON o.CustomerID = c.CustomerID GROUP BY c.Name; -> Option B
Quick Check:
INNER JOIN with GROUP BY customer name sums orders [OK]

Quick Trick: Join Orders to Customers, group by customer name for totals [OK]

Common Mistakes:

MISTAKES

Using LEFT JOIN includes customers without orders
Grouping by wrong column
Joining tables in wrong order causing confusion

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You have two tables:

Step 1: Understand requirement - total per customer with orders only

Step 2: Check query correctness

Step 3: Compare other options

Final Answer:

Quick Check:

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