Subquery Quiz

What is a subquery?

• A command to delete data

• A type of database

• An SQL query nested inside a larger query

• A query that is executed independently

Where can subqueries be nested?

• Only inside SELECT statements

• Inside SELECT, INSERT, UPDATE, DELETE, SET, or DO statements

• Only inside UPDATE statements

• Only inside DELETE statements

What is a correlated subquery?

• A subquery that runs independently

• A subquery that cannot return results

• A subquery that contains a reference to a table in the outer query

• A subquery that is always nested

What does the SELECT clause do in a subquery?

• Updates existing records

• Filters records based on conditions

• Returns data based on specific criteria

• Defines a temporary table

What is the purpose of the FROM clause in a subquery?

• To delete records

• To return a single value

• To define a temporary table for the main query

• To filter records

What does the WHERE clause do in a subquery?

• Updates records

• Filters records based on certain conditions

• Returns multiple rows of data

• Defines a temporary table

What type of result can a subquery return?

• Only a single column of data

• A single or multiple rows of data

• Only a single row

• Only a single value

What is a scalar result in the context of subqueries?

• A single value

• Multiple rows of data

• A temporary table

• Multiple columns of data

What does a subquery often perform?

• Only data deletion

• Only data retrieval

• Complex operations requiring multiple steps

• Simple operations

How does MySQL evaluate a correlated subquery?

• Not at all

• Simultaneously

• From inside to outside

• From outside to inside