Why string manipulation is common in MySQL - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the first 5 characters of the name column.

MySQL

SELECT [1](name, 5) FROM employees;

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

ARIGHT

BCONCAT

CSUBSTRING_INDEX

DLEFT

Attempts:

3 left

💡 Hint

Common Mistakes

Using RIGHT instead of LEFT

Using CONCAT which joins strings

Using SUBSTRING_INDEX incorrectly

The LEFT function extracts the leftmost characters from a string. Here, it gets the first 5 characters of the name.

2fill in blank

medium

Complete the code to find the position of 'a' in the city column.

MySQL

SELECT [1]('a', city) FROM locations;

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ALOCATE

BFIND

CINSTR

DPOSITION

Attempts:

3 left

💡 Hint

Common Mistakes

Using POSITION which is standard SQL but less common in MySQL

Using FIND which is not a MySQL function

The LOCATE function returns the position of a substring in a string. It returns the first occurrence of 'a' in city.

3fill in blank

hard

Fix the error in the code to convert the email column to lowercase.

MySQL

SELECT [1](email) FROM users;

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ALOWER

BLOWERCASE

CTOLOWER

DUPPER

Attempts:

3 left

💡 Hint

Common Mistakes

Using UPPER which converts to uppercase

Using LOWERCASE or TOLOWER which are not valid MySQL functions

The correct function to convert text to lowercase in MySQL is LOWER. Other options are invalid or do not exist.

4fill in blank

hard

Fill both blanks to extract the domain from an email address.

MySQL

SELECT SUBSTRING(email, [1], [2]) AS domain FROM users;

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ALOCATE('@', email) + 1

BLENGTH(email)

CLOCATE('@', email) - 1

DCHAR_LENGTH(email)

Attempts:

3 left

💡 Hint

Common Mistakes

Using LOCATE('@', email) - 1 which points before '@'

Using LENGTH which is similar but may not handle multibyte characters correctly

The domain starts right after '@', so we add 1 to its position for the start. The length is the total length of the email minus the position of '@' to get the rest of the string.

5fill in blank

hard

Fill all three blanks to create a query that replaces 'old' with 'new' in the description column and trims spaces.

MySQL

SELECT TRIM([1](description, [2], [3])) AS updated_desc FROM products;

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AREPLACE

B'old'

C'new'

DSUBSTRING

Attempts:

3 left

💡 Hint

Common Mistakes

Using SUBSTRING which extracts parts but does not replace

Not trimming spaces after replacement

The REPLACE function replaces all occurrences of 'old' with 'new' in the description. Then TRIM removes extra spaces around the result.