MELINIA - SEQUELVERSE - ROUND 1

Which of the following commands is used to delete all rows and free up space from a table?

• TRUNCATE

• DELETE

• ALTER

• DROP

Which of the following is not a valid SQL type?

• FLOAT

• NUMERIC

• DECIMAL

• CHARACTER

Which of the following is a legal expression in SQL?

•  SELECT NULL FROM EMPLOYEE;

• SELECT NAME FROM EMPLOYEE;

•  SELECT NAME FROM EMPLOYEE WHERE SALARY = NULL;

• None of the above

Which of the following is a comparison operator in SQL?

• =

• LIKE

• BETWEEN

• All of the above

1. Which statement is true regarding the INTERSECT operator?

• It ignores NULL values

• Reversing the order of the intersected tables alters the result

• The names of columns in all SELECT statements must be identical

• The number of columns and data types must be identical for all SELECT statements in the query

1. Which SQL statement is used to update data in a table?

• MODIFY table_name SET column_name = value;

• UPDATE table_name SET column_name = value;

• CHANGE table_name SET column_name = value;

• ALTER table_name SET column_name = value;

Which SQL statement is used to limit the number of results returned from a query?

1. How do you filter the Employees table to show only the rows where the Age is greater than 30?

• SELECT * FROM Employees WHERE Age > 30; 

• SELECT * FROM Employees HAVING Age > 30;

• SELECT * FROM Employees WHERE Age >= 30;

• SELECT * FROM Employees FILTER BY Age > 30;

 What is the purpose of the JOIN clause in SQL?

• It filters the rows returned by the SELECT statement.

• It specifies the columns to be retrieved.

•  It combines rows from two or more tables based on a related column.

• It orders the results in ascending or descending order. 

1. What type of join is needed when you wish to include rows that do not have matching values?

• • Equi-join

• • Natural join

• Outer join

• All of the above