Selection operation 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;

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

AALL_COLUMNS

B*

CANY

DALL

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ALL' instead of '*'

Using 'ANY' which is not valid here

Using 'ALL_COLUMNS' which is not a SQL keyword

The asterisk (*) symbol is used in SQL to select all columns from a table.

2fill in blank

medium

Complete the code to select rows where the 'age' column is greater than 30.

DBMS Theory

SELECT * FROM employees WHERE age [1] 30;

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

A=

B<=

C<

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' which selects only equal values

Using '<' which selects smaller values

Using '<=' which includes smaller or equal values

The '>' operator selects rows where the value is greater than the specified number.

3fill in blank

hard

Fix the error in the code to select employees with the last name 'Smith'.

DBMS Theory

SELECT * FROM employees WHERE last_name [1] 'Smith';

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

A=

BLIKE

C==

DIS

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' which is invalid in SQL

Using 'LIKE' without wildcards for exact match

Using 'IS' which is for NULL comparisons

In SQL, '=' is used to compare values for equality. '==' is not valid in SQL.

4fill in blank

hard

Fill both blanks to select employees with salary greater than 50000.

DBMS Theory

SELECT * FROM employees WHERE salary [1] [2];

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

A>

B50000

C40000

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>'

Using 40000 instead of 50000

Swapping the blanks

The '>' operator selects salaries greater than the number 50000.

5fill in blank

hard

Fill all three blanks to select employees with age less than 40 and department 'Sales'.

DBMS Theory

SELECT * FROM employees WHERE age [1] [2] AND department [3] 'Sales';

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

A<

B40

C=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' instead of '<' for age

Using wrong age number

Using 'LIKE' instead of '=' for department

The code filters employees younger than 40 and in the 'Sales' department using '<', '40', and '=' operators.