SQL Querying Relational Data Statements

In a school database, what is the purpose of the SQL SELECT statement when Samuel wants to view the grades of his classmates?

• To retrieve data from a database.

• To update existing records in a database.

• To delete data from a database.

• To create a new database table.

Answer explanation

The SQL SELECT statement is specifically designed to retrieve data from a database, making it the correct choice. The other options pertain to different SQL commands for updating, deleting, or creating tables.

Mia wants to find all the students who scored above 80 in their exams. How does she filter records in SQL using the WHERE clause?

• Use the WHERE clause to specify conditions for filtering records in SQL.

• Filtering records is done using the GROUP BY clause.

• The WHERE clause is used to join tables in SQL.

• Use the SELECT statement to retrieve all records.

Answer explanation

The correct choice highlights that the WHERE clause is essential for filtering records in SQL by specifying conditions. Other options incorrectly describe the functions of GROUP BY, table joins, and the SELECT statement.

Nora is trying to understand how the AND operator works in SQL queries. What is the function of the AND operator in SQL queries?

• The AND operator is used to combine results from different tables.

• The AND operator allows any condition to be true.

• The AND operator requires all conditions to be true.

• The AND operator is only applicable in SELECT statements.

Answer explanation

The AND operator in SQL requires that all specified conditions must be true for a record to be included in the results. This is why the correct answer is that the AND operator requires all conditions to be true.

In a group project, how does the OR operator differ from the AND operator when deciding on tasks among Abigail, Jackson, and Elijah?

• The OR operator allows for flexibility in conditions, whereas the AND operator requires all conditions to be met.

• The OR operator requires all conditions to be met, while the AND operator allows for flexibility.

• The OR operator is used for sorting tasks, whereas the AND operator is used for filtering tasks.

• The OR operator can only be used with numeric values, while the AND operator can be used with any data type.

Answer explanation

The OR operator allows for flexibility by returning true if any condition is met, while the AND operator requires all specified conditions to be true for a result. This distinction is crucial for constructing effective SQL queries.

Write an SQL query to select all columns from a table named 'Students' where the student name is 'Liam'.

• SELECT Students;

• SELECT ALL FROM Students;

• GET * FROM Students;

• SELECT * FROM Students;

Answer explanation

The correct SQL query to select all columns from a table is 'SELECT * FROM Students;'. The asterisk (*) signifies all columns, while the other options are incorrect syntax.

How would you use the WHERE clause to find students like Noah and Lily with a grade above 85?

• SELECT * FROM students WHERE grade < 85;

• SELECT * FROM students WHERE grade > 85;

• SELECT * FROM students WHERE grade >= 85;

• SELECT name, grade FROM students;

Answer explanation

The correct choice is 'SELECT * FROM students WHERE grade > 85;' because it accurately retrieves students with grades strictly above 85, which is the requirement stated in the question.

Ava is trying to add a new student record to the school database. What is the syntax for inserting a new record into a table?

• INSERT INTO table_name VALUES (value1, value2);

• INSERT INTO table_name (column1, column2) VALUES (value1, value2);

• ADD RECORD INTO table_name (column1, column2) VALUES (value1, value2);

• INSERT table_name (column1, column2) SET (value1, value2);

Answer explanation

The correct syntax for inserting a new record into a table is 'INSERT INTO table_name (column1, column2) VALUES (value1, value2);'. This specifies the table and the columns for the values being inserted.

Write an SQL INSERT query to add a new student named 'John Doe' with a grade of 90.

• INSERT INTO students (name) VALUES ('John Doe');

• INSERT INTO students VALUES ('John Doe', 90);

• INSERT INTO students (student_name, score) VALUES ('John Doe', 90);

• INSERT INTO students (name, grade) VALUES ('John Doe', 90);

Answer explanation

The correct query is 'INSERT INTO students (name, grade) VALUES ('John Doe', 90);' because it specifies both the columns 'name' and 'grade' to insert the values correctly. Other options are incomplete or incorrect.

How does Hannah update an existing record in her SQL database?

• UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition;

• SELECT * FROM table_name WHERE condition;

• INSERT INTO table_name VALUES (value1, value2);

• DELETE FROM table_name WHERE condition;

Answer explanation

To update an existing record in SQL, use the UPDATE statement. The correct syntax is: UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition; This modifies specified columns for records that meet the condition.

Write an SQL UPDATE query to change 'John Doe's' grade to 95.

• UPDATE students SET grade = 95 WHERE name = 'John Doe';

• UPDATE students SET grade = '95' WHERE name = 'Aiden';

• UPDATE students SET grade = 90 WHERE name = 'Luna';

• UPDATE students SET name = 'John Doe' WHERE grade = 95;

Answer explanation

The correct query is 'UPDATE students SET grade = 95 WHERE name = 'John Doe';' because it accurately updates John Doe's grade to 95. The other options either have incorrect names, grades, or do not match the requirement.