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WGU C427 OBJECTIVE ASSESSMENT FINAL
EXAM NEWEST 2025/2026 COMPLETE 300
QUESTIONS AND CORRECT ANSWERS WITH
RATIONALES (VERIFIED ANSWERS) |ALREADY
GRADED A+||BRAND NEW VERSION!!
How do you limit the number of rows returned by a SELECT statement in MySQL? - ANSWER-SELECT *\nFROM TableName\nLIMIT 100;
Describe the structure of a SELECT statement with a WHERE clause. - ANSWER-SELECT Expression1, Expression2, ...\nFROM TableName\nWHERE Condition;
Refer to the City table. What cities are selected by the following statement?\nSELECT *\nFROM City \nWHERE Population < 150000;\nCity\nID Name CountryCode District Population\n207 Rio de Janeiro BRA Rio de Janeiro 5598953\n462 Manchester GBR England 430000\n554 Santiago CHL Santiago 4703954\n654 Barcelona ESP Katalonia 1503451\n826 Valencia PHL Northern Mindanao 147924\n1025 Delhi IND Delhi 7206704 - ANSWER-Valencia
Refer to the City table. What cities are selected by the following statement?\nSELECT *\nFROM City \nWHERE ID <= 1000 \nAND ID >= 600;\nCity\nID Name CountryCode District Population\n207 Rio de 1 / 4
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Janeiro BRA Rio de Janeiro 5598953\n462 Manchester GBR England 430000\n554 Santiago CHL Santiago 4703954\n654 Barcelona ESP Katalonia 1503451\n826 Valencia PHL Northern Mindanao 147924\n1025 Delhi IND Delhi 7206704 - ANSWER-Barcelona, Valencia
Refer to the City table. What cities are selected by the following statement?\nSELECT *\nFROM City \nWHERE ID < 300 \nOR Population > 7500000;\nCity\nID Name CountryCode District Population\n207 Rio de Janeiro BRA Rio de Janeiro 5598953\n462 Manchester GBR England 430000\n554 Santiago CHL Santiago 4703954 - ANSWER-ID Name CountryCode District Population 207 Rio de Janeiro BRA Rio de Janeiro 5598953
What is NULL in relational databases, and how is it different from zero or blank values? - ANSWER-NULL is a special value that represents either unknown or inapplicable data. It is not the same as zero for numeric data types or blanks for character data types.
Refer to the Compensation table. What does a NULL in the Name column represent, and what does a zero in the Bonus column represent?\nCompensation\nID Name Department Salary Bonus\n2538 Lisa Ellison Engineering 45000 NULL\n5384 Sam Snead Sales 30500 1000\n6381 Maria Rodriguez Sales 92300 3000 - ANSWER-- NULL in the Name column represents either unknown or inapplicable data.\n- A zero in the Bonus column represents that Lisa Ellison has earned no bonus. 2 / 4
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What is the NOT NULL constraint, and how is it applied in a CREATE TABLE statement? - ANSWER-The NOT NULL constraint prevents a column from having a NULL value. It follows the column name and data type in a CREATE TABLE statement.\n```sql\nCREATE TABLE Department (\n Code TINYINT UNSIGNED NOT NULL,\n Name VARCHAR(20),\n ManagerID SMALLINT\n);\n```
Which columns in the following CREATE TABLE statement may contain NULL values?\n```sql\nCREATE TABLE Department (\n Code TINYINT UNSIGNED NOT NULL,\n Name VARCHAR(20),\n ManagerID SMALLINT\n);\n``` - ANSWER-The Name and ManagerID columns may contain NULL values.
What happens when arithmetic or comparison operators have one or more NULL operands? - ANSWER-The result is NULL. When a WHERE clause evaluates to NULL for values in a row, the row is not selected.
Refer to the Compensation table. What names are selected by the following statement?\n```sql\nSELECT Name\nFROM Compensation\nWHERE (Salary + Bonus) > 30000;\n```\nCompensation\nID Name Department Salary Bonus\n2538 Lisa Ellison Engineering 45000 NULL\n5384 Sam Snead Sales 30500 1000\n6381 Maria Rodriguez Sales 92300 3000 - ANSWER- Sam Snead, Maria Rodriguez 3 / 4
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How do you select rows with NULL values in SQL? - ANSWER-Use the IS
NULL or IS NOT NULL operators. Example:\n```sql\nSELECT *\nFROM
Employee\nWHERE Salary IS NULL;\n```
Refer to the Country table. Write a SELECT statement to retrieve all rows where IndepYear is NULL.\nCountry\nCode Name HeadOfState IndepYear Population\nABW Aruba Beatrix NULL 103000\nAIA Anguilla Charles III 1920 NULL\nAFG Afghanistan Mohammad Omar 1919 22720000\nAGO Angola Jose dos Santos 1975 12878000 - ANSWER- ```sql\nSELECT *\nFROM Country\nWHERE IndepYear IS NULL;\n```
How does NULL affect logical expressions in SQL? - ANSWER-In SQL, logical expressions may be TRUE, FALSE, or NULL. NULL indicates the
value of a logical expression is uncertain. Examples:\n- `TRUE AND
NULL` is NULL\n- `FALSE AND NULL` is FALSE\n- `NULL OR TRUE` is TRUE
Refer to the Compensation table. What names are selected by the following statement?\n```sql\nSELECT Name\nFROM Compensation\nWHERE Salary > 30000 OR Bonus > 1000;\n```\nCompensation\nID Name Department Salary Bonus\n2538 Lisa Ellison Engineering 115000 NULL\n5348 Sam Snead Sales 35000 55000\n6381 Maria Rodriguez Sales 95000 3000 - ANSWER-Lisa Ellison, Sam Snead, Maria Rodriguez
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