Keep products without fees · Study guide
Identify the required rows and columns and decide how to group the conditions. Open the practice screen to write SQL and inspect the results.
From Products(products), show Name(name) → Shipping fee (KRW)(shipping_fee) in this order. Connect the data using LEFT JOIN · Shipping fees by category(categories). Match rows when Category(products.category) = Category name(categories.category_name). At the JOIN step, keep all left-table rows; unmatched right-side values are NULL.
Learning objectives and tables
- Name (name)
- Shipping fee (KRW) (shipping_fee)
- LEFT JOIN · Shipping fees by category (categories)
- (Category (products.category) = Category name (categories.category_name))
- At the JOIN step, keep all left-table rows; unmatched right-side values are NULL.
products (Products): id (ID), name (Name), category (Category), price (Price (KRW)), stock (Stock)
categories (Shipping fees by category): category_name (Category name), shipping_fee (Shipping fee (KRW))
Concepts to review
Practice: Keep products without fees
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