The problem asks for a SQL query that returns the number of unique visitors to a website each day. The input is a table with visitor IDs and dates, and the output should be a table with dates and the corresponding number of unique visitors.
This technical problem involves writing a SQL query to find all pairs of records in two tables, A and B, where A.id = B.id and A.val < B.val .
This technical problem deals with writing a SQL query that returns the number of products in each category. The input is given in the form of two tables - one for products and one for categories - and the expected output is also given in table form.
This technical problem involves writing a SQL query to find the total number of orders for each customer. The input is two tables - the customer table and the orders table. The output is the customer id and the number of orders for each customer.
This technical problem involves writing a SQL query to find the name and email address of all customers who have made at least one purchase from the store. The input is given in the form of two tables: customers and purchases. The customers table includes columns for id, name, and email, while the purchases table includes columns for id, customer_id, and product. The desired output is a table with columns for name and email, listing all customers who have made at least one purchase.
Write a SQL query to join two tables, table1 and table2, and return all columns from both tables.
This technical problem asks the reader to write a SQL query that returns the names of all employees who work in the Sales or Marketing department.
Write a SQL query to find all the rows in table A that have a corresponding row in table B.