D426 Data Management Foundations - Set 2 - Part 1

Correct Answer: ORDER BY DESC

The ORDER BY DESC clause sorts the query results in descending order by the specified column(s).

Correct Answer: TEXT

The TEXT data type is suitable for storing large textual data in a relational database.

Correct Answer: UNIQUE

The UNIQUE keyword ensures that all values in a column are distinct, preventing duplicate entries in that column.

Correct Answer: COUNT

The COUNT function returns the number of non-NULL rows in a result set.

Correct Answer: IN

The IN operator checks if a value exists in a list of specified values.

Correct Answer: Foreign Key

A Foreign Key allows NULL values and is used to establish relationships between tables by referencing the primary key in another table.

Correct Answer: DISTINCT

The DISTINCT keyword removes duplicate rows from the result of a SELECT query, returning only unique rows.

Correct Answer: UPPER

The UPPER function converts all characters in a string to uppercase in SQL.

Correct Answer: B-Tree Index

B-Tree indexes are optimized for queries that involve range-based searches, as they allow efficient traversal through ordered data.

Correct Answer: Composite Key

A Composite Key is a combination of two or more columns that together uniquely identify each row in a table.

Correct Answer: MAX

The MAX function returns the highest value from a specified column in SQL.

Correct Answer: GROUP BY

The GROUP BY clause groups rows that share the same values in the specified columns, often used with aggregate functions.

Correct Answer: CREATE USER

The CREATE USER command is used to create a new database user account, which can then be granted specific privileges.

Correct Answer: DISTINCT

The DISTINCT clause ensures that only unique values are returned from the specified column, removing duplicates.

Correct Answer: UNION

The UNION clause is used to combine the results of two SELECT queries into a single result set, excluding duplicates.

Correct Answer: LIMIT

The LIMIT keyword restricts the number of rows returned by a SELECT query to a specified number.

Correct Answer: CHECK

The CHECK constraint ensures that the values in a column meet a specified condition or rule.

Correct Answer: Self-Join

A Self-Join occurs when a table is joined to itself, often used to compare rows within the same table.

Correct Answer: HAVING

The HAVING clause is used to apply conditions to groups created by the GROUP BY clause, filtering the results after grouping.

Correct Answer: To speed up data retrieval

Indexes are used to improve the performance of queries by allowing the database to locate and retrieve rows more quickly.