ICTPRG431 - SQL Joins and Subqueries

What are the different types of joins in SQL?

• INNER, LEFT, RIGHT, and OUTER

• PRIMARY, FOREIGN, and NATURAL

• SELECT, INSERT, UPDATE, and DELETE

• GROUP BY, HAVING, and ORDER BY

How can you simulate joins that are not directly supported?

• By using subqueries

• By using UNION operator

• By using GROUP BY clause

• By using WHERE clause

In which real-world scenarios would different types of joins be useful?

• When combining data from multiple tables

• When sorting data in ascending order

• When filtering data based on conditions

• When updating records in a table

What is the difference between correlated and noncorrelated subqueries?

• Correlated subqueries depend on the outer query, while noncorrelated subqueries do not

• Correlated subqueries are used for INSERT statements, while noncorrelated subqueries are used for SELECT statements

• Correlated subqueries can only be nested once, while noncorrelated subqueries can be nested multiple times

• Correlated subqueries are faster than noncorrelated subqueries

Which statements can contain nested subqueries?

• SELECT, INSERT, UPDATE, and DELETE

• SELECT and INSERT

• SELECT and UPDATE

• SELECT and DELETE

What is the purpose of subqueries in the WHERE clause?

• To filter the result set based on a condition

• To join multiple tables together

• To sort the result set in ascending order

• To update records in a table

How do you construct a subquery?

• By enclosing the subquery in parentheses

• By using the keyword SUBQUERY

• By using the keyword JOIN

• By using the keyword SUBSELECT

What is the purpose of the FROM clause subquery?

• To use the result of the subquery as a table in the main query

• To filter the result set based on a condition

• To sort the result set in ascending order

• To update records in a table