DA SQL and Database Querying 2

Question 1

Which SQL function returns the current date and time?

Accepted Answer

NOW()

Answer

DATE()

Answer

GETTIME()

Answer

CURRENT()

Question 2

What is a subquery in SQL?

Accepted Answer

A query nested inside another query

Answer

A query stored as a view

Answer

A query that joins multiple tables

Answer

A query that modifies table structure

Question 3

What does the GROUP BY clause do in SQL?

Accepted Answer

Aggregates rows sharing the same value in specified columns

Answer

Joins tables on matching columns

Answer

Sorts the result set

Answer

Filters rows before the query executes

Question 4

Which SQL join returns only the rows where there is a match in both tables?

Accepted Answer

INNER JOIN

Answer

LEFT JOIN

Answer

RIGHT JOIN

Answer

FULL OUTER JOIN

Question 5

What is the purpose of an index in a database?

Accepted Answer

Speed up data retrieval operations

Answer

Enforce referential integrity

Answer

Prevent duplicate entries

Answer

Define the data type of a column

Question 6

Which SQL function calculates a running total within a window of rows?

Accepted Answer

SUM() OVER ()

Answer

CUMSUM()

Answer

RUNNING_TOTAL()

Answer

AGGREGATE()