Write subqueries to select data from multiple tables.
Create subqueries to return a single value or multiple values.
Use subqueries in the SELECT, FROM, WHERE, and HAVING clauses.
Understand and use correlated subqueries, which depend on values from the outer query.
Use subqueries to solve problems such as finding maximum or minimum values and records that don't have corresponding entries in other tables.
Understand the difference between IN, EXISTS, and ANY/ALL operators in subqueries.
How to use subqueries to create more complex queries and better understand the structure and relationships in a database.