To put it simply, CTE or Common Table Expression turns a query or subquery into a temporary table. In other words, CTE tables derive from other queries. CTE creates that temporary table so you could use it to narrow down your results further using the columns you’ve selected inside of that query. The use cases for CTEs are similar to that of subqueries, but CTEs will vastly improve the readability of these code scripts. For Example, when we write long scripts, having multiple subqueries can easily confuse people, whereas CTEs organize those queries into separate chunks; in other words, it modularizes the chunks of code. Therefore, the use of CTEs will significantly speed up the debugging process.