Basic Sql question :\n1. How will you improve performance of table\n2. Where vs Having difference\n3. what is CTE and subquery, When will you use CTE and when will you use Subquery\n\nSQL live coding session:\n\nGiven following 2 tables :\nPrime (Customerid,prime_Status,start_date,end_date)\nSales (customerid,orderid,orderday,productid,quanity sold)\n\nQuestion 1: How many units were sold on each of the last 7 days?\nQuestion 2: How many unique customers made a purchase 15 days ago and how many were prime members?\nQuestion 3: Which customer purchased the most units on each of the last 5 days (assume no ties)?

Basic Sql question :\n1. How will you improve performance of table\n2. Where vs Having difference\n3. what is CTE and subquery, When will you use CTE and when w