WGU C170 THE MOST IMPORTANT SQL COMMANDS (SQL STUDY GUIDE) QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF
Core Domains
SQL Query Basics and SELECT Statements
Data Manipulation (INSERT, UPDATE, DELETE)
Table Management (CREATE, ALTER, DROP)
JOIN Operations and Table Relationships
Filtering and Conditional Logic (WHERE, BETWEEN, IN)
Aggregate Functions and Grouping (GROUP BY, HAVING)
Sorting and Limiting Results (ORDER BY, LIMIT)
Database Normalization and Primary/Foreign Keys
SQL Syntax and Statement Structure
Professional Ethics and Data Compliance Standards
Introduction
,This comprehensive assessment evaluates mastery of the most critical SQL commands essential for database applications and data management
professionals. The exam tests foundational theoretical knowledge alongside applied professional skills required for real-world database querying,
manipulation, and administration. Candidates will encounter multiple-choice questions and scenario-based problems that emphasize practical
decision-making in authentic workplace contexts. The assessment covers SELECT statements, data manipulation commands, table management
operations, JOIN techniques, filtering clauses, aggregate functions, sorting mechanisms, and database normalization principles. Success requires
not only memorizing syntax but understanding when and how to apply each command appropriately while adhering to professional ethics and
regulatory compliance standards governing data handling.
Section One: Questions 1–100
Question 1
What is the primary purpose of the SELECT statement in SQL?
A. To modify existing data in a table
B. To extract data from a database
C. To delete records from a table
D. To create a new database
🟢 B. To extract data from a database
🔴 RATIONALE: The SELECT command is fundamentally designed to extract/query data from a database. According to SQL fundamentals,
SELECT extracts data from a database while UPDATE modifies data, DELETE removes data, and CREATE DATABASE creates new databases.
Question 2
Which SQL command is used to add new rows into a table?
A. SELECT
B. UPDATE
C. INSERT
D. DELETE
🟢 C. INSERT
🔴 RATIONALE: The INSERT command (specifically INSERT INTO) adds new rows into a table. This is one of the top 5 basic SQL commands,
where SELECT retrieves data, INSERT adds rows, UPDATE modifies data, DELETE removes data, and JOIN combines tables.
,Question 3
What clause is used to filter records in a SQL query based on specified conditions?
A. ORDER BY
B. GROUP BY
C. WHERE
D. HAVING
🟢 C. WHERE
🔴 RATIONALE: The WHERE clause filters records based on specified conditions before any grouping occurs. It applies conditional criteria to
individual rows, while HAVING applies conditions to grouped rows after GROUP BY.
Question 4
Which SQL command updates existing data in a database?
A. SELECT
B. UPDATE
C. INSERT
D. CREATE
🟢 B. UPDATE
🔴 RATIONALE: The UPDATE command modifies/updates data in a database. This is confirmed in the SQL cheat sheet where SELECT extracts
data, UPDATE updates data, DELETE deletes data, and INSERT INTO inserts new data.
Question 5
What is the correct syntax for joining two tables on a shared key?
A. SELECT * FROM table1 JOIN table2
B. SELECT * FROM table1 JOIN table2 ON table1.key = table2.key
C. SELECT * FROM table1, table2 WHERE key
D. SELECT * JOIN table1, table2 ON key
🟢 B. SELECT * FROM table1 JOIN table2 ON table1.key = table2.key
, 🔴 RATIONALE: When combining two tables, you must JOIN them on columns that are equal (the shared primary/foreign key). The correct syntax
specifies FROM table1 JOIN table2 ON table1.key = table2.key, as shown in the WGU C170 tips.
Question 6
Which aggregate function counts the number of rows in a result set?
A. SUM()
B. AVG()
C. COUNT()
D. MAX()
🟢 C. COUNT()
🔴 RATIONALE: COUNT() is the aggregate method that counts rows. WGU C170 exam content specifically focuses on aggregate methods including
COUNT, SUM, AVG, MIN, and MAX as key topics.
Question 7
What clause orders the results of a SQL query?
A. WHERE
B. ORDER BY
C. GROUP BY
D. HAVING
🟢 B. ORDER BY
🔴 RATIONALE: ORDER BY sorts/orders the results of a query. The WGU C170 exam is heavily focused on syntax including ORDER BY, which
sorts results typically with ASC (ascending) or DESC (descending) options.
Question 8
Which SQL command deletes data from a database?
ANSWERS) PLUS RATIONALES 2026 Q&A | INSTANT DOWNLOAD PDF
Core Domains
SQL Query Basics and SELECT Statements
Data Manipulation (INSERT, UPDATE, DELETE)
Table Management (CREATE, ALTER, DROP)
JOIN Operations and Table Relationships
Filtering and Conditional Logic (WHERE, BETWEEN, IN)
Aggregate Functions and Grouping (GROUP BY, HAVING)
Sorting and Limiting Results (ORDER BY, LIMIT)
Database Normalization and Primary/Foreign Keys
SQL Syntax and Statement Structure
Professional Ethics and Data Compliance Standards
Introduction
,This comprehensive assessment evaluates mastery of the most critical SQL commands essential for database applications and data management
professionals. The exam tests foundational theoretical knowledge alongside applied professional skills required for real-world database querying,
manipulation, and administration. Candidates will encounter multiple-choice questions and scenario-based problems that emphasize practical
decision-making in authentic workplace contexts. The assessment covers SELECT statements, data manipulation commands, table management
operations, JOIN techniques, filtering clauses, aggregate functions, sorting mechanisms, and database normalization principles. Success requires
not only memorizing syntax but understanding when and how to apply each command appropriately while adhering to professional ethics and
regulatory compliance standards governing data handling.
Section One: Questions 1–100
Question 1
What is the primary purpose of the SELECT statement in SQL?
A. To modify existing data in a table
B. To extract data from a database
C. To delete records from a table
D. To create a new database
🟢 B. To extract data from a database
🔴 RATIONALE: The SELECT command is fundamentally designed to extract/query data from a database. According to SQL fundamentals,
SELECT extracts data from a database while UPDATE modifies data, DELETE removes data, and CREATE DATABASE creates new databases.
Question 2
Which SQL command is used to add new rows into a table?
A. SELECT
B. UPDATE
C. INSERT
D. DELETE
🟢 C. INSERT
🔴 RATIONALE: The INSERT command (specifically INSERT INTO) adds new rows into a table. This is one of the top 5 basic SQL commands,
where SELECT retrieves data, INSERT adds rows, UPDATE modifies data, DELETE removes data, and JOIN combines tables.
,Question 3
What clause is used to filter records in a SQL query based on specified conditions?
A. ORDER BY
B. GROUP BY
C. WHERE
D. HAVING
🟢 C. WHERE
🔴 RATIONALE: The WHERE clause filters records based on specified conditions before any grouping occurs. It applies conditional criteria to
individual rows, while HAVING applies conditions to grouped rows after GROUP BY.
Question 4
Which SQL command updates existing data in a database?
A. SELECT
B. UPDATE
C. INSERT
D. CREATE
🟢 B. UPDATE
🔴 RATIONALE: The UPDATE command modifies/updates data in a database. This is confirmed in the SQL cheat sheet where SELECT extracts
data, UPDATE updates data, DELETE deletes data, and INSERT INTO inserts new data.
Question 5
What is the correct syntax for joining two tables on a shared key?
A. SELECT * FROM table1 JOIN table2
B. SELECT * FROM table1 JOIN table2 ON table1.key = table2.key
C. SELECT * FROM table1, table2 WHERE key
D. SELECT * JOIN table1, table2 ON key
🟢 B. SELECT * FROM table1 JOIN table2 ON table1.key = table2.key
, 🔴 RATIONALE: When combining two tables, you must JOIN them on columns that are equal (the shared primary/foreign key). The correct syntax
specifies FROM table1 JOIN table2 ON table1.key = table2.key, as shown in the WGU C170 tips.
Question 6
Which aggregate function counts the number of rows in a result set?
A. SUM()
B. AVG()
C. COUNT()
D. MAX()
🟢 C. COUNT()
🔴 RATIONALE: COUNT() is the aggregate method that counts rows. WGU C170 exam content specifically focuses on aggregate methods including
COUNT, SUM, AVG, MIN, and MAX as key topics.
Question 7
What clause orders the results of a SQL query?
A. WHERE
B. ORDER BY
C. GROUP BY
D. HAVING
🟢 B. ORDER BY
🔴 RATIONALE: ORDER BY sorts/orders the results of a query. The WGU C170 exam is heavily focused on syntax including ORDER BY, which
sorts results typically with ASC (ascending) or DESC (descending) options.
Question 8
Which SQL command deletes data from a database?
