SQL Practice Problems - Day 9
Focus: Date/Time Functions and Calendar Logic

1 - Extract year, month, and day from sales dates.
Input Table: Sales_Transactions
Output: Sale_ID, Date, Year, Month, Day

2 - Find sales that occurred on weekends.
Input Table: Sales_Transactions
Output: Sale_ID, Date, Day_Of_Week

3 - Calculate the number of days between order date and current date.
Input Table: Sales_Transactions
Output: Sale_ID, Date, Days_Since_Sale

4 - List products sold in Q2 (April-June) of any year.
Input Tables: Sales_Transactions, Products
Output: SKU_Code, Design_No, Date

5 - Show warehouse operations from the last 30 days.
Input Table: Warehouse_Ops
Output: Operation_ID, Operation_Type, Date

6 - Calculate average sales by day of week.
Input Table: Sales_Transactions
Output: Day_Of_Week, Avg_Sales

7 - Find customers who made purchases on consecutive days.
Input Tables: Customers, Sales_Transactions
Output: Customer_ID, Customer_Name, Purchase_Dates

8 - Identify products with sales peaks in specific months.
Input Tables: Products, Sales_Transactions
Output: SKU_Code, Peak_Month, Monthly_Sales

9 - Calculate the time between warehouse inbound and outbound operations.
Input Table: Warehouse_Ops
Output: SKU_Code, Inbound_Date, Outbound_Date, Days_In_Warehouse

10 - Show monthly sales growth percentages year-over-year.
Input Table: Sales_Transactions
Output: Month, Current_Year_Sales, Previous_Year_Sales, Growth_Pct

11 - Convert all timestamps to UTC timezone for reporting.
Input Table: Warehouse_Ops
Output: Operation_ID, Original_Timestamp, UTC_Timestamp

12 - Find the busiest hour of day for sales.
Input Table: Sales_Transactions
Output: Hour_Of_Day, Transaction_Count

13 - Calculate customer purchase frequency in days.
Input Tables: Customers, Sales_Transactions
Output: Customer_ID, Avg_Days_Between_Purchases

14 - Identify seasonal products with 80% of sales in 3 consecutive months.
Input Tables: Products, Sales_Transactions
Output: SKU_Code, Seasonal_Months, Pct_Total_Sales

15 - Generate a complete calendar date dimension table for 2021-2023.
Input: None
Output: Date, Day_Of_Week, Month, Quarter, Year, Is_Weekend