Category: 8. Subqueries

Introduction: What Exactly is a Subquery? (The Secret Note) Common Use Cases (Our Detective Cases!): Explain: “First, we find the average price of all products (that’s our secret note!). Then, we look at all the products again and only show the ones that cost more than that average.” Explain: “For each customer, we go and count how many orders they have in the orders list (that’s our secret count!). Then we show the customer’s name and their secret order count.” Explain: “We look at each customer. For each customer, we secretly check if there’s at least one order in the…

Hey everyone! Imagine you have a big box of LEGOs, and inside that big box, you have several smaller boxes. Now, imagine you need to find a specific red brick in each of those smaller boxes. To do that, you have to open each small box one by one and look inside. Well, in the world of databases and MySQL, we have something similar called correlated subqueries. It’s like having a small question (the subquery) inside a bigger question (the main query), and the answer to the small question depends on something in the bigger question! Think of it this…

Let’s dive into the wonderful world of subqueries in MySQL’s SELECT statement! Imagine you’re like a super detective, and sometimes you need to ask another detective for information to help you solve your main case. That’s kind of what a subquery is! Imagine our database has two main tables: Column What it holds Example CustID A unique number for each customer 101 CustName The name of the customer Alice City The city where the customer lives Toyville Column What it holds Example OrderID A unique number for each order 1 CustID The ID of the customer who placed the order…