Database Query Challenge

What is a database query?

• A request for data or information from a database

• A type of computer virus

• A type of internet browser

• A method for organizing files on a computer

What are the different types of database queries?

• search, browse, download, upload, share

• copy, paste, cut, save, print

• add, subtract, multiply, divide, calculate

• select, insert, update, delete, join

Explain the SELECT statement in SQL.

• The SELECT statement in SQL is used to update data in a database.

• The SELECT statement in SQL is used to retrieve data from a database.

• The SELECT statement in SQL is used to create a new database.

• The SELECT statement in SQL is used to delete data from a database.

What is the purpose of the WHERE clause in a database query?

• To order the results of the query alphabetically

• To perform mathematical calculations on the query results

• To filter the rows returned by a database query based on a specified condition.

• To display all the rows in the database without any filtering

What is the difference between the LIKE and = operators in a database query?

• The LIKE operator is used for pattern matching, allowing for the use of wildcards such as % and _. The = operator, on the other hand, is used for exact matching.

• The LIKE operator can only be used with strings, while the = operator can be used with any data type.

• The LIKE operator is case-sensitive, while the = operator is case-insensitive.

• The LIKE operator is used for numeric values, while the = operator is used for text values.

Explain the concept of JOIN in database queries.

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

• JOIN is used to delete rows from a table based on a related column

• JOIN is used to create a new table based on a related column

• JOIN is used to update rows in a table based on a related column

What is the role of the ORDER BY clause in a database query?

• It is used to sort the result set of a database query.

• It is used to create a new database table

• It is used to update the schema of the database

• It is used to delete data from the database

What is the purpose of the GROUP BY clause in a database query?

• To delete the result set

• To group the result set by one or more columns

• To update the result set

• To order the result set by one or more columns

Explain the concept of subqueries in database queries.

• Subqueries are only used in NoSQL databases

• Subqueries can only be used with numeric data types

• Subqueries are queries nested within another query.

• Subqueries are used to update multiple tables at once

What are the common mistakes to avoid when writing database queries?

• Optimizing queries properly

• Using SELECT * instead of specifying columns

• Not using parameterized queries

• Improper indexing, using SELECT * instead of specifying columns, not using parameterized queries, not optimizing queries, not handling errors properly