D492 Data Analytics Applications - Set 2 - Part 3

Correct Answer: To combine rows from multiple tables based on related columns

The JOIN clause is used to combine rows from multiple tables based on a related column. It does not insert data, remove duplicates, or filter rows.

Correct Answer: BETWEEN

The BETWEEN operator is used to select values within a specific range. LIKE is used for pattern matching, IN checks if a value is within a list, and EXISTS checks if a subquery returns any rows.

Correct Answer: AS

The AS keyword is used to rename a column in the result set. RENAME is not used for columns in query results, FROM specifies the table, and SELECT retrieves data.

Correct Answer: To return the number of rows

The COUNT() function returns the number of rows in the result set. SUM() adds numeric values, AVG() calculates the average, and MAX() returns the maximum value.

Correct Answer: WHERE

The WHERE clause filters rows based on a specified condition. GROUP BY groups rows, ORDER BY sorts rows, and DISTINCT removes duplicate rows.

Correct Answer: A query that is nested inside another query

A subquery is a query that is nested inside another query, typically in the WHERE or FROM clause. It is used to perform additional filtering or calculations within the main query.

Correct Answer: DISTINCT

The DISTINCT clause removes duplicate rows from the result set. GROUP BY groups rows based on column values, ORDER BY sorts rows, and WHERE filters rows.

Correct Answer: EXISTS

The EXISTS operator is used to check if a subquery returns any rows. If the subquery returns one or more rows, EXISTS evaluates to TRUE. IN checks if a value is within a list, LIKE is used for pattern matching, and BETWEEN checks if a value falls within a range.

Correct Answer: CREATE DATABASE

The CREATE DATABASE command is used to create a new database. CREATE TABLE is used to create a new table, INSERT INTO adds data to a table, and ALTER DATABASE modifies the structure of a database.

Correct Answer: Filters groups after aggregation

The HAVING clause is used to filter groups after aggregation, typically used with GROUP BY. WHERE filters rows before aggregation, ORDER BY sorts the result set, and JOIN combines rows from two tables.