You want to create a view that shows the total sales per customer from the Sales table with columns customer_id and amount. Which SQL correctly creates this view?
hard📝 Application Q8 of 15
SQL - Views
You want to create a view that shows the total sales per customer from the Sales table with columns customer_id and amount. Which SQL correctly creates this view?
ACREATE VIEW CustomerSales AS SELECT customer_id, amount FROM Sales;
BCREATE VIEW CustomerSales AS SELECT customer_id, SUM(amount) AS total FROM Sales GROUP BY customer_id;
CCREATE VIEW CustomerSales AS SELECT customer_id, COUNT(amount) FROM Sales;
DCREATE VIEW CustomerSales AS SELECT customer_id, SUM(amount) FROM Sales;
Step-by-Step Solution
Solution:
Step 1: Identify aggregation needed
You want total sales per customer, so SUM(amount) grouped by customer_id is required.
Step 2: Check each option
CREATE VIEW CustomerSales AS SELECT customer_id, SUM(amount) AS total FROM Sales GROUP BY customer_id; uses SUM(amount) with GROUP BY customer_id correctly; others miss grouping or use wrong aggregation.
Final Answer:
CREATE VIEW CustomerSales AS SELECT customer_id, SUM(amount) AS total FROM Sales GROUP BY customer_id; -> Option B
Quick Check:
Aggregation with GROUP BY needed = CREATE VIEW CustomerSales AS SELECT customer_id, SUM(amount) AS total FROM Sales GROUP BY customer_id; [OK]
Quick Trick:Use GROUP BY with aggregation in views for summaries [OK]
Common Mistakes:
MISTAKES
Omitting GROUP BY with aggregation
Using COUNT instead of SUM for totals
Not aliasing aggregated columns
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