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ALTER TABLE orders
  ADD COLUMN shipping_method ENUM('standard','in_store') NOT NULL DEFAULT 'standard' AFTER shipping_cost
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ERROR 1060 (42S21) at line 10: Duplicate column name 'shipping_method'
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CREATE INDEX idx_orders_shipping_method ON orders (shipping_method, status)
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ERROR 1061 (42000) at line 14: Duplicate key name 'idx_orders_shipping_method'