How SQL communicates with the database engine - 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'

A*

BALL

Ccolumns

Deverything

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ALL' instead of '*'

Writing 'columns' which is not valid SQL syntax

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

2fill in blank

medium

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

SQL

SELECT * FROM users 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 means less than

Using '=' which means equal to

The '>' operator filters rows where age is greater than 30.

3fill in blank

hard

Fix the error in the SQL query to count the number of rows in the 'orders' table.

SQL

SELECT COUNT([1]) FROM orders;

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

Aorder_id

Brows

Call

D*

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column name that might have NULLs and cause incorrect counts

Using 'all' or 'rows' which are not valid SQL keywords here

Using COUNT(*) counts all rows in the table.

4fill in blank

hard

Fill both blanks to select the 'name' and 'salary' columns from 'employees' where salary is at least 50000.

SQL

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

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

Aname

Bsalary

Cage

Ddepartment

Attempts:

3 left

💡 Hint

Common Mistakes

Selecting columns not related to the condition

Mixing up column names

We select 'name' and 'salary' columns to see employees earning at least 50000.

5fill in blank

hard

Fill all three blanks to create a query that selects 'product', counts 'sales', and filters where sales are more than 100.

SQL

SELECT [1], COUNT([2]) FROM sales_data GROUP BY [3] HAVING COUNT([2]) > 100;

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

Aproduct

Bsale_id

Dcustomer

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong columns in COUNT or GROUP BY

Not matching COUNT column in HAVING clause

The query groups sales by product, counts sales by sale_id, and filters groups with more than 100 sales.