As you may have understood from previous chapters, an inner subquery creates a table with which we then perform operations in the outer query.

From this, we can conclude that we can also use an inner query within the FROM section to select something from this table.

Let's consider an example where we need to work with employees whose salary is above a certain value. But instead of a WHERE clause, we will use an inner query:

We've created a new table using an inner subquery with which we can work and gather information.

Note

Notice that for such a table, it's essential to provide an alias.

When might this be useful?

Such a query is highly readable; sometimes, it can replace a WHERE clause.

Additionally, if you need to work not with the entire table but only with a filtered part, an inner subquery within the FROM section can be extremely handy.

Now, let's move on to a small task!

In this task, we'll be working with the department table.

Let me remind you what it looks like:

Note

This task could also be done using a WHERE clause, but we use a nested query here to practice this syntax, which will be useful for solving more complex problems in the future.