SQL Database Quiz

What is SQL?

• Structured Query Logic

• Sequential Query Language

• System Query Language

• Structured Query Language

Name three common SQL data types.

• String, Boolean, Decimal

• Float, Char, Boolean

• Integer, Varchar, Date

• Text, Number, Boolean

What is the syntax for a basic SQL query?

• SELECT column1, column2, ... FROM table_name;

• SELECT column1, column2 FROM table_name WHERE condition;

• SELECT column1, column2 FROM table_name;

• SELECT * FROM table_name;

What is a SQL join and how does it work?

• A SQL join is used to combine rows from two or more tables based on a related column between them.

• A SQL join is used to combine rows from two or more tables based on a common value in a non-related column.

• A SQL join is used to combine rows from two or more tables based on a primary key column.

• A SQL join is used to combine rows from two or more tables based on a random column.

What are the different types of SQL joins?

• cross join

• self join

• natural join

• inner join, left join, right join, full outer join

What are SQL aggregation functions used for?

• SQL aggregation functions are used to perform calculations on a set of values and return a single value as the result.

• SQL aggregation functions are used to create new tables in a database.

• SQL aggregation functions are used to update records in a database.

• SQL aggregation functions are used to sort data in a database.

Give an example of an SQL aggregation function.

• COUNT()

• MAX()

• MIN()

• SUM()

What is the difference between WHERE and HAVING clauses in SQL?

• The WHERE clause is used to filter groups, while the HAVING clause is used to filter rows.

• The WHERE clause is used to filter rows, while the HAVING clause is used to filter groups.

• The WHERE clause is used to filter columns, while the HAVING clause is used to filter tables.

• The WHERE clause is used to sort data, while the HAVING clause is used to join tables.

What is the purpose of GROUP BY clause in SQL?

• The purpose of the GROUP BY clause in SQL is to sort the rows in ascending order based on specified column(s).

• The purpose of the GROUP BY clause in SQL is to join multiple tables together based on a common column.

• The purpose of the GROUP BY clause in SQL is to group rows based on specified column(s) and perform aggregate calculations on each group separately.

• The purpose of the GROUP BY clause in SQL is to filter out rows that do not meet a specified condition.

Explain the concept of subqueries in SQL.

• Subqueries in SQL are used to create new tables in the database.

• Subqueries in SQL are used to delete data from the database.

• Subqueries in SQL are nested queries used to retrieve data and use it as a condition or criteria for the outer query.

• Subqueries in SQL are used to update data in the database.