SQL Subqueries vs. CTEs: A Guide to Writing Better Queries

When you first learn SQL, queries are usually straightforward: you SELECT some columns from a table and apply a WHERE filter to narrow down the results. As your data questions become more complex, however, you realize sometimes you need the answer to one question before you can answer another. For example: "Which employees earn above the company average?" , requires calculating the average salary first, then use the result to filter employees. To solve this, SQL provides two incredibly powerful