How the database engine processes a SELECT in SQL - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

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

SQL

SELECT [1] FROM employees;

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

AALL

BCOLUMNS

CEVERY

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ALL' instead of '*'

Writing '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 the 'name' column from the 'employees' table.

SQL

SELECT [1] FROM employees;

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

Aname

Bemployee_name

CName

Dnames

Attempts:

3 left

💡 Hint

Common Mistakes

Using plural 'names' instead of 'name'

Using a different column name not in the table

The column name is 'name' exactly as in the table schema.

3fill in blank

hard

Fix the error in the SELECT statement to retrieve 'salary' from 'employees'.

SQL

SELECT salary FROM [1];

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

Aemployees

Bemployee

Cemployes

Demployee_table

Attempts:

3 left

💡 Hint

Common Mistakes

Misspelling the table name

Using singular form instead of plural

The correct table name is 'employees'. Misspelling it causes an error.

4fill in blank

hard

Fill both blanks to select 'name' and 'salary' columns from 'employees'.

SQL

SELECT [1], [2] FROM employees;

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

Aname

Bsalary

Cage

Ddepartment

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting wrong columns like 'age' or 'department'

Swapping the order of columns (order matters for output)

We select the columns 'name' and 'salary' as requested.

5fill in blank

hard

Fill all three blanks to select 'name' and 'salary' from 'employees' where salary is greater than 50000.

SQL

SELECT [1], [2] FROM [3] WHERE salary > 50000;

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

Aname

Bsalary

Cemployees

Dsalaries

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong table name like 'salaries'

Selecting columns not requested

Omitting the WHERE clause (not asked here but important)

The query selects 'name' and 'salary' columns from the 'employees' table with a condition on salary.