WGU Data-Management-Foundations Exam Dumps

The ORDER BY clause in SQL is used to sort query results in ascending (ASC) or descending (DESC) order.

Example Usage:

sql

SELECT Name, Salary FROM Employees ORDER BY Salary DESC;

This retrieves all employees, sorted by salary in descending order.

Why Other Options Are Incorrect:

Option A (BETWEEN) (Incorrect): Used for filtering ranges but does not order results.

Option B (DISTINCT) (Incorrect): Removes duplicate rows but does not control order.

Option D (LIKE) (Incorrect): Used for pattern matching, not sorting.

Thus, ORDER BY is the correct choice for defining the sequence of query results.

A simple primary key consists of only one column that uniquely identifies each row in a table.

Example Usage:

sql

CREATE TABLE Students (

StudentID INT PRIMARY KEY,

Name VARCHAR(50)

);

StudentID is a simple primary key because it consists of only one field.

Why Other Options Are Incorrect:

Option B (Partition) (Incorrect): Refers to partitioned tables, which divide data for performance reasons but are not related to primary keys.

Option C (Stable) (Incorrect): This is not a recognized term in database keys.

Option D (Meaningless) (Incorrect): Primary keys are often meaningless (e.g., auto-incremented IDs), but this is not a term used to describe their structure.

Thus, the correct answer is Simple, as a single-field primary key is referred to as a simple primary key.

The correct syntax for deleting records from a table in SQL is:

sql

DELETE FROM table_name WHERE condition;

This deletes only the rows that match the condition.

Example Usage:

sql

DELETE FROM Employees WHERE Salary < 30000;

Deletes all employees earning less than $30,000.

Why Other Options Are Incorrect:

Option A (Incorrect): Missing FROM keyword. The correct syntax is DELETE FROM table_name.

Option C (Partially Correct): DELETE FROM table_name; deletes all rows, but it lacks a WHERE clause.

Option D (Incorrect): DELETE * is not valid in SQL. The correct command is just DELETE FROM.

Thus, the correct answer is DELETE FROM table_name WHERE condition;.

The MERGE statement, also known as UPSERT, combines INSERT, UPDATE, and DELETE operations into a single statement based on a given condition. It is commonly used in data warehouses and large-scale databases.

Example Usage:

sql

MERGE INTO Employees AS Target

USING NewEmployees AS Source

ON Target.ID = Source.ID

WHEN MATCHED THEN

UPDATE SET Target.Salary = Source.Salary

WHEN NOT MATCHED THEN

INSERT (ID, Name, Salary) VALUES (Source.ID, Source.Name, Source.Salary);

If a match is found, the UPDATE clause modifies the existing record.

If no match is found, the INSERT clause adds a new record.

Why Other Options Are Incorrect:

Option A (INTO) (Incorrect): Used in INSERT INTO, but does not combine operations.

Option B (JOIN) (Incorrect): Used to combine rows from multiple tables, but not for merging data.

Option D (DROP) (Incorrect): Deletes database objects like tables, views, and indexes, but does not merge data.

Thus, the correct answer is MERGE, as it combines inserts, updates, and deletes into a single operation.

In MySQL, the BIGINT data type is a 64-bit integer that requires 8 bytes (64 bits) of storage. It is used to store large numerical values beyond the range of INT (4 bytes).

Option A (Incorrect): 1 byte corresponds to TINYINT, which can store values from -128 to 127.

Option B (Incorrect): 3 bytes is not a standard integer storage size in MySQL.

Option C (Incorrect): 4 bytes corresponds to INT, which has a range of -2,147,483,648 to 2,147,483,647.

Option D (Correct): BIGINT takes 8 bytes and supports a massive range of numbers from -2^63 to 2^63 -1.