Intermediate level sql quiz

Which SQL clause is used to join two tables on a common column?

JOIN

INNER JOIN

OUTER JOIN

LEFT JOIN

What is the purpose of the `GROUP_CONCAT()` function in SQL?

It concatenates multiple rows into a single string

It groups rows by a specific column

It finds the maximum value in a column

It calculates the average value of a column

Which of the following SQL commands will return only unique rows?

SELECT DISTINCT

SELECT UNIQUE

SELECT NO DUPLICATES

SELECT DIFFERENT

What is the difference between `INNER JOIN` and `LEFT JOIN`?

`INNER JOIN` returns only matching rows, `LEFT JOIN` returns all rows from the left table

`INNER JOIN` returns all rows, `LEFT JOIN` returns matching rows

`INNER JOIN` returns rows with null values

`LEFT JOIN` returns only matching rows

Which SQL function is used to get the number of rows in a result set?

COUNT()

TOTAL()

SUM()

NUMBER()

Which of the following SQL statements is used to update multiple rows at once?

UPDATE

INSERT

SELECT

MODIFY

Which SQL clause is used to define the condition for joining tables?

WHERE

ON

HAVING

JOIN

What is the purpose of the `COALESCE()` function in SQL?

It returns the first non-NULL value in a list of arguments

It replaces NULL values with a default value

It checks for null values

It counts the number of NULL values in a column

Which SQL statement would you use to combine the results of two `SELECT` statements while eliminating duplicates?

UNION

INTERSECT

JOIN

COMBINE

What does the `HAVING` clause do in SQL?

Filters the rows before grouping

Filters the rows after grouping

Sorts the result set

Counts the number of rows in a group