Question 1

You can use the EXISTS operator to retrieve data from more than one table.

Accepted Answer

The EXISTS operator in SQL is used to check for the existence of any record in a subquery and can be utilized to perform operations that involve more than one table by specifying a correlated subquery that references another table.

Question 2

When a subquery involves a table listed in the outer query, the subquery is called a(n) _____.
A) inner outer subquery
B) correlated subquery
C) reverse subquery
D) parameter subquery

Accepted Answer

A correlated subquery is a type of subquery that uses values from the outer query in its WHERE clause. The subquery is executed repeatedly, once for each row that might be selected by the outer query.

Question 3

In which type of join will all rows from the table listed second in the query be included regardless of whether they match rows from the table listed first in the query?
A) left inner join
B) left outer join
C) right outer join
D) right inner join

Accepted Answer

In a right outer join, all rows from the table listed second (right side of the join) are included in the result set, regardless of whether there is a matching row in the table listed first (left side of the join). This means even if there are no matching rows in the first table, the rows from the second table will still appear in the output, with NULLs in the columns of the first table where there is no match.

Question 4

To retrieve data from multiple tables in a query, you can use a subquery containing the _____.
A) AND operator
B) IN operator
C) OR operator
D) NOT operator

Accepted Answer

The IN operator allows you to specify multiple values in a WHERE clause, making it suitable for subqueries that retrieve data from multiple tables by matching a set of values obtained from another table.

Question 5

You create an alias by typing the name of the table, pressing the _____, and then typing the name of the alias.
A) Tab key
B) Backspace key
C) Enter key
D) Spacebar

Accepted Answer

To create an alias for a table in SQL, you type the name of the table followed by a space and then the alias name. The spacebar is used to separate the table name from the alias name.

Question 6

A condition is true if it satisfies any value (one or more) produced by a subquery that is preceded by the _____.
A) IS SOME operator
B) ALL operator
C) SOME operator
D) ANY operator

Accepted Answer

The answer of A condition is true if it satisfies...

Question 7

You can join tables by using a condition in the _____.
A) FROM clause
B) WHERE clause
C) SELECT clause
D) JOIN clause

Accepted Answer

The answer of You can join tables by using a...

Question 8

The _____ of two tables is a table containing every row that is in either the first table, the second table, or both tables.
A) intersection
B) union
C) minus
D) difference

Accepted Answer

The union of two tables combines all rows from both tables, including duplicates, to form a new table.

Question 9

When is it necessary to qualify a column name while joining tables in MySQL?
A) It is necessary when the tables have identical column names.
B) It is necessary when the tables have different column names.
C) It is never necessary when you join tables in MySQL.
D) It is necessary every time you join tables in MySQL.

Accepted Answer

Qualifying a column name is necessary when joining tables that have identical column names to avoid ambiguity. This tells the database system specifically which table's column you are referring to.

Question 10

When using a DBMS without an optimizer, the formulation of a query can make a difference in the speed with which the query is executed.

Accepted Answer

Without an optimizer, the DBMS does not automatically optimize the execution plan for a query. Therefore, how the query is formulated can significantly impact the execution speed, as the system will execute the query exactly as it is written without making any adjustments for efficiency.

Question 11

The ____ of two tables is the set of all rows that are in the first table but that are not in the second table.
A) union
B) inner join
C) intersection
D) difference

Accepted Answer

The difference between two tables, often referred to as the "set difference," includes all rows that are in the first table but not in the second table. This operation is akin to subtracting one set from another in set theory.

Question 12

You can use the IN operator to retrieve data from multiple tables.

Accepted Answer

The answer of You can use the IN operator to...

Question 13

The _____ of two tables is a table containing all rows that are in both tables.
A) intersection
B) union
C) difference
D) minus

Accepted Answer

The intersection of two tables includes only the rows that are present in both tables, matching the definition provided.

Question 14

To create a condition that is true if one or more rows are obtained when the subquery is executed, you can precede that subquery with which operator?
A) IS NULL
B) IS TRUE
C) IS EXIST
D) EXISTS

Accepted Answer

The EXISTS operator is used in SQL to test for the existence of any record in a subquery. If the subquery returns one or more records, the condition is considered true.

Question 15

The product of two tables is formally called the _____.
A) inner join
B) outer join
C) SQL product
D) Cartesian product

Accepted Answer

The product of two tables, without any conditions specified, is formally called the Cartesian product. This operation combines each row of the first table with each row of the second table, resulting in a table that has the number of rows equal to the product of the number of rows in the two original tables.

Question 16

Nina is writing a MySQL query to list the descriptions of items in the CUPCAKES table, which are identified by PROD_ID values. The ORDER_LINE table includes product and quantity information from bakery orders, which are identified by ORDER_NUM values. What can she add to the following query to limit the list to descriptions of cupcakes purchased through order 342? SELECT DESCRIPTION FROM CUPCAKES WHERE
A) PROD_ID IN(ORDER_LINE WHERE(ORDER_NUM = '342'));
B) EXISTS (PROD_ID WHERE (ORDER_LINE.ORDER_NUM = '342'));
C) PROD_ID IN(SELECT PROD_ID FROM ORDER_LINE WHERE(ORDER_NUM = '342'));
D) PROD_ID EXISTS(SELECT PROD_ID FROM ORDER_LINE WHERE(ORDER_NUM = '342'));

Accepted Answer

C) is correct because it uses a subquery to select PROD_ID values from the ORDER_LINE table where the ORDER_NUM is '342', and then uses these values to filter the DESCRIPTIONS from the CUPCAKES table where the PROD_ID matches those selected by the subquery.

Question 17

In a nested query, the outer query is evaluated first.

Accepted Answer

In a nested query, the inner query is evaluated first, and its result is then used by the outer query.

Question 18

In which type of join are all rows from the table listed first in the query included, regardless of whether they match rows from the table listed second in the query?
A) left inner join
B) left outer join
C) right inner join
D) right outer join

Accepted Answer

A left outer join includes all rows from the first (left) table listed in the query, regardless of whether there is a matching row in the second (right) table.

Question 19

You can use the ALL and ANY operators with subqueries to produce a single column of numbers.

Accepted Answer

The ALL and ANY operators are used in SQL with subqueries that return multiple values to compare a value to each value in a list or subquery result, effectively allowing you to produce or work with a single column of numbers in comparisons.

Question 20

To qualify a column name, precede the name of the column with the name of the table, followed by a(n) _____.
A) comma (,)
B) period (.)
C) percent sign (%)
D) asterisk (*)

Accepted Answer

To qualify a column name with the table name, a period (.) is used between the table name and the column name. This syntax is commonly used in SQL to distinguish between columns of different tables that may have the same name when joining tables in a query.

Quiz 5: Multiple Table Queries

You can use the EXISTS operator to retrieve data from more than one table.

When a subquery involves a table listed in the outer query, the subquery is called a(n) _____.

In which type of join will all rows from the table listed second in the query be included regardless of whether they match rows from the table listed first in the query?

To retrieve data from multiple tables in a query, you can use a subquery containing the _____.

You create an alias by typing the name of the table, pressing the _____, and then typing the name of the alias.

A condition is true if it satisfies any value (one or more) produced by a subquery that is preceded by the _____.

You can join tables by using a condition in the _____.

The _____ of two tables is a table containing every row that is in either the first table, the second table, or both tables.

When is it necessary to qualify a column name while joining tables in MySQL?

When using a DBMS without an optimizer, the formulation of a query can make a difference in the speed with which the query is executed.

The ____ of two tables is the set of all rows that are in the first table but that are not in the second table.

You can use the IN operator to retrieve data from multiple tables.

The _____ of two tables is a table containing all rows that are in both tables.

To create a condition that is true if one or more rows are obtained when the subquery is executed, you can precede that subquery with which operator?

The product of two tables is formally called the _____.

In a nested query, the outer query is evaluated first.

In which type of join are all rows from the table listed first in the query included, regardless of whether they match rows from the table listed second in the query?

You can use the ALL and ANY operators with subqueries to produce a single column of numbers.

To qualify a column name, precede the name of the column with the name of the table, followed by a(n) _____.