SELECT with WHERE, ORDER BY, GROUP BY in DBMS Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select all columns from the table named 'employees'.

DBMS Theory

SELECT [1] FROM employees;

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Acolumns

BALL

C*

Deverything

Attempts:

3 left

💡 Hint

Common Mistakes

Writing 'ALL' instead of '*'

Using 'columns' which is not valid SQL syntax

The asterisk (*) means select all columns from the table.

2fill in blank

medium

Complete the code to select employees with salary greater than 50000.

DBMS Theory

SELECT name, salary FROM employees WHERE salary [1] 50000;

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A<

B>

C=

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' which selects salaries less than 50000

Using '=' which selects salaries exactly 50000

The '>' operator filters rows where salary is greater than 50000.

3fill in blank

hard

Fix the error in the code to order employees by their hire date in ascending order.

DBMS Theory

SELECT name, hire_date FROM employees ORDER BY hire_date [1];

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AUP

BDESC

CDOWN

DASC

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'DESC' which sorts in descending order

Using 'UP' or 'DOWN' which are not valid SQL keywords

'ASC' means ascending order, which sorts from oldest to newest.

4fill in blank

hard

Fill both blanks to group employees by department and count how many are in each.

DBMS Theory

SELECT [1], COUNT(*) FROM employees GROUP BY [2];

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Adepartment

Bsalary

Cdepartment_id

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Grouping by 'name' which is unique per employee

Selecting 'salary' which is not a grouping column

We select the department name and group by department name to count employees per department.

5fill in blank

hard

Fill all three blanks to select department names, average salary, and order results by average salary descending.

DBMS Theory

SELECT [1], AVG([2]) FROM employees GROUP BY [3] ORDER BY AVG(salary) DESC;

Drag options to blanks, or click blank then click option'

Adepartment_name

Bsalary

Demployee_id

Attempts:

3 left

💡 Hint

Common Mistakes

Grouping by employee_id which is unique per row

Averaging department_name which is not numeric

We select department_name, calculate average salary, group by department_name, and order by average salary descending.