WGU C992 – Advanced Data Management Comprehensive
WGU-Style Practice Exam Questions and Answers
1. Which SQL clause is used to retrieve data from a database table?
A) FETCH
B) GET
C) SELECT
D) READ
Answer: C
SELECT is the primary SQL command used to retrieve data from one or more tables. It
allows filtering, sorting, and grouping of data. SELECT forms the foundation of most
SQL operations. WGU heavily emphasizes understanding SELECT behavior.
2. Which JOIN returns all rows from the left table and matching rows from the right table?
A) INNER JOIN
B) LEFT JOIN
C) RIGHT JOIN
D) FULL JOIN
Answer: B
LEFT JOIN returns all records from the left table and only matching records from the
right table. Rows without matches on the right return NULL values. This join is
commonly used in reporting scenarios. WGU often tests join logic conceptually.
3. What is the purpose of a primary key?
A) To allow duplicate values
B) To uniquely identify each row
C) To speed up inserts
D) To store foreign keys
Answer: B
A primary key uniquely identifies each row in a table. It must contain unique values and
cannot be NULL. Primary keys enforce entity integrity. WGU frequently includes
questions on key constraints.
4. Which SQL command is used to change existing data in a table?
A) INSERT
B) UPDATE
C) ALTER
D) MODIFY
Answer: B
UPDATE modifies existing rows in a table. It is usually combined with a WHERE clause
to target specific records. Without a WHERE clause, all rows are updated. WGU often
tests awareness of this risk.
5. Which aggregate function returns the total number of rows?
A) SUM
B) COUNT
C) AVG
, D) MAX
Answer: B
COUNT returns the number of rows that meet a specified condition. COUNT(*) includes
all rows, including those with NULL values. It is commonly used with GROUP BY.
WGU uses COUNT in reporting-based questions.
6. Which clause groups rows that share common values?
A) WHERE
B) ORDER BY
C) GROUP BY
D) HAVING
Answer: C
GROUP BY organizes rows so aggregate functions can be applied. It is required when
using aggregates with non-aggregated columns. GROUP BY executes before HAVING.
WGU tests SQL execution order frequently.
7. What does the HAVING clause filter?
A) Individual rows
B) Columns
C) Aggregated results
D) Indexes
Answer: C
HAVING filters results after aggregation has occurred. It works with GROUP BY and
aggregate functions. WHERE cannot filter aggregated values. This distinction is a classic
WGU exam topic.
8. Which normal form removes partial dependencies?
A) 1NF
B) 2NF
C) 3NF
D) BCNF
Answer: B
Second Normal Form removes partial dependencies on a composite primary key. All
non-key attributes must depend on the entire key. This applies only when composite keys
exist. WGU often uses composite-key scenarios.
9. What is a foreign key used for?
A) Enforcing uniqueness
B) Improving performance
C) Establishing table relationships
D) Encrypting data
Answer: C
A foreign key links a table to a primary key in another table. It enforces referential
integrity. Foreign keys prevent orphan records. WGU frequently tests parent-child
relationships.
10. Which database object improves query performance on frequently searched columns?
A) View
B) Trigger
C) Index
D) Function
Answer: C
Indexes improve query performance by reducing search time. They act like a lookup
, structure for data. While they speed up reads, they can slow down writes. WGU often
balances performance trade-offs in questions.
11. Which SQL statement is used to remove all rows from a table while keeping the table
structure intact?
A) DROP
B) DELETE
C) TRUNCATE
D) REMOVE
Answer: C
TRUNCATE removes all rows from a table but preserves the table definition and
structure. It is faster than DELETE because it does not log individual row deletions.
TRUNCATE cannot be rolled back in most databases. WGU frequently tests the
difference between DELETE and TRUNCATE.
12. What is the primary key used for in a database table?
A) To allow duplicate records
B) To uniquely identify each row
C) To improve query speed only
D) To store foreign keys
Answer: B
A primary key uniquely identifies each record in a table. It cannot contain NULL values
and must be unique. Primary keys help enforce entity integrity. WGU often includes
primary key rules in scenario questions.
13. Which JOIN returns only matching rows from both tables?
A) LEFT JOIN
B) RIGHT JOIN
C) FULL JOIN
D) INNER JOIN
Answer: D
INNER JOIN returns rows only when there is a match in both tables. Rows without
matching values are excluded from the result set. This is the most commonly used join
type. WGU tests join behavior conceptually rather than syntax-heavy.
14. What is the purpose of the GROUP BY clause?
A) To sort data
B) To filter records
C) To aggregate rows by column
D) To limit results
Answer: C
GROUP BY groups rows that share a common value so aggregate functions can be
applied. It is required when using aggregate functions with non-aggregated columns.
GROUP BY executes before HAVING. This execution order is frequently tested.
15. Which aggregate function returns the total number of rows?
A) SUM
B) COUNT
C) AVG
D) MAX
Answer: B
COUNT returns the number of rows that match a specified condition. COUNT(*)
WGU-Style Practice Exam Questions and Answers
1. Which SQL clause is used to retrieve data from a database table?
A) FETCH
B) GET
C) SELECT
D) READ
Answer: C
SELECT is the primary SQL command used to retrieve data from one or more tables. It
allows filtering, sorting, and grouping of data. SELECT forms the foundation of most
SQL operations. WGU heavily emphasizes understanding SELECT behavior.
2. Which JOIN returns all rows from the left table and matching rows from the right table?
A) INNER JOIN
B) LEFT JOIN
C) RIGHT JOIN
D) FULL JOIN
Answer: B
LEFT JOIN returns all records from the left table and only matching records from the
right table. Rows without matches on the right return NULL values. This join is
commonly used in reporting scenarios. WGU often tests join logic conceptually.
3. What is the purpose of a primary key?
A) To allow duplicate values
B) To uniquely identify each row
C) To speed up inserts
D) To store foreign keys
Answer: B
A primary key uniquely identifies each row in a table. It must contain unique values and
cannot be NULL. Primary keys enforce entity integrity. WGU frequently includes
questions on key constraints.
4. Which SQL command is used to change existing data in a table?
A) INSERT
B) UPDATE
C) ALTER
D) MODIFY
Answer: B
UPDATE modifies existing rows in a table. It is usually combined with a WHERE clause
to target specific records. Without a WHERE clause, all rows are updated. WGU often
tests awareness of this risk.
5. Which aggregate function returns the total number of rows?
A) SUM
B) COUNT
C) AVG
, D) MAX
Answer: B
COUNT returns the number of rows that meet a specified condition. COUNT(*) includes
all rows, including those with NULL values. It is commonly used with GROUP BY.
WGU uses COUNT in reporting-based questions.
6. Which clause groups rows that share common values?
A) WHERE
B) ORDER BY
C) GROUP BY
D) HAVING
Answer: C
GROUP BY organizes rows so aggregate functions can be applied. It is required when
using aggregates with non-aggregated columns. GROUP BY executes before HAVING.
WGU tests SQL execution order frequently.
7. What does the HAVING clause filter?
A) Individual rows
B) Columns
C) Aggregated results
D) Indexes
Answer: C
HAVING filters results after aggregation has occurred. It works with GROUP BY and
aggregate functions. WHERE cannot filter aggregated values. This distinction is a classic
WGU exam topic.
8. Which normal form removes partial dependencies?
A) 1NF
B) 2NF
C) 3NF
D) BCNF
Answer: B
Second Normal Form removes partial dependencies on a composite primary key. All
non-key attributes must depend on the entire key. This applies only when composite keys
exist. WGU often uses composite-key scenarios.
9. What is a foreign key used for?
A) Enforcing uniqueness
B) Improving performance
C) Establishing table relationships
D) Encrypting data
Answer: C
A foreign key links a table to a primary key in another table. It enforces referential
integrity. Foreign keys prevent orphan records. WGU frequently tests parent-child
relationships.
10. Which database object improves query performance on frequently searched columns?
A) View
B) Trigger
C) Index
D) Function
Answer: C
Indexes improve query performance by reducing search time. They act like a lookup
, structure for data. While they speed up reads, they can slow down writes. WGU often
balances performance trade-offs in questions.
11. Which SQL statement is used to remove all rows from a table while keeping the table
structure intact?
A) DROP
B) DELETE
C) TRUNCATE
D) REMOVE
Answer: C
TRUNCATE removes all rows from a table but preserves the table definition and
structure. It is faster than DELETE because it does not log individual row deletions.
TRUNCATE cannot be rolled back in most databases. WGU frequently tests the
difference between DELETE and TRUNCATE.
12. What is the primary key used for in a database table?
A) To allow duplicate records
B) To uniquely identify each row
C) To improve query speed only
D) To store foreign keys
Answer: B
A primary key uniquely identifies each record in a table. It cannot contain NULL values
and must be unique. Primary keys help enforce entity integrity. WGU often includes
primary key rules in scenario questions.
13. Which JOIN returns only matching rows from both tables?
A) LEFT JOIN
B) RIGHT JOIN
C) FULL JOIN
D) INNER JOIN
Answer: D
INNER JOIN returns rows only when there is a match in both tables. Rows without
matching values are excluded from the result set. This is the most commonly used join
type. WGU tests join behavior conceptually rather than syntax-heavy.
14. What is the purpose of the GROUP BY clause?
A) To sort data
B) To filter records
C) To aggregate rows by column
D) To limit results
Answer: C
GROUP BY groups rows that share a common value so aggregate functions can be
applied. It is required when using aggregate functions with non-aggregated columns.
GROUP BY executes before HAVING. This execution order is frequently tested.
15. Which aggregate function returns the total number of rows?
A) SUM
B) COUNT
C) AVG
D) MAX
Answer: B
COUNT returns the number of rows that match a specified condition. COUNT(*)
