TRIM, LTRIM, RTRIM in SQL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to remove spaces from both ends of the string ' hello '.

SQL

SELECT [1]('  hello  ') AS trimmed_text;

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

ALTRIM

BREMOVE

CRTRIM

DTRIM

Attempts:

3 left

💡 Hint

Common Mistakes

Using LTRIM or RTRIM removes spaces only from one side.

Using a non-existent function like REMOVE causes errors.

The TRIM function removes spaces from both the left and right ends of a string.

2fill in blank

medium

Complete the code to remove spaces only from the left side of the string ' world '.

SQL

SELECT [1]('  world  ') AS left_trimmed;

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

ATRIM

BCLEAN

CLTRIM

DRTRIM

Attempts:

3 left

💡 Hint

Common Mistakes

Using TRIM removes spaces from both sides, not just left.

Using RTRIM removes spaces from the right side.

LTRIM removes spaces only from the left (start) of the string.

3fill in blank

hard

Fix the error in the code to remove spaces only from the right side of the string ' data '.

SQL

SELECT [1]('  data  ') AS right_trimmed;

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

ARTRIM

BLTRIM

CTRIM

DREMOVE

Attempts:

3 left

💡 Hint

Common Mistakes

Using LTRIM removes spaces from the left side.

Using TRIM removes spaces from both sides.

RTRIM removes spaces only from the right (end) of the string.

4fill in blank

hard

Fill both blanks to remove spaces from the left and right sides of the string ' example '.

SQL

SELECT [1]([2]('  example  ')) AS cleaned;

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

ALTRIM

BTRIM

CRTRIM

DREMOVE

Attempts:

3 left

💡 Hint

Common Mistakes

Using TRIM inside LTRIM is redundant because TRIM alone removes both sides.

Using REMOVE causes errors.

Using RTRIM inside LTRIM removes spaces from right first, then left.

5fill in blank

hard

Fill all three blanks to remove spaces from both ends and then convert the string ' SQL ' to uppercase.

SQL

SELECT UPPER([1]([2]([3]('  SQL  ')))) AS result;

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

ALTRIM

BRTRIM

CTRIM

DREMOVE

Attempts:

3 left

💡 Hint

Common Mistakes

Using REMOVE causes errors.

Mixing up LTRIM and RTRIM order.

First, TRIM removes spaces both sides, then RTRIM and LTRIM are redundant but here the order is TRIM then RTRIM then LTRIM (though TRIM alone suffices). Finally, UPPER converts to uppercase.

Practice

1. What does the SQL function LTRIM do to a string?

easy

A. Removes all spaces inside the string

B. Removes spaces only from the end (right side) of the string

C. Removes spaces from both the start and end of the string

D. Removes spaces only from the start (left side) of the string

Solution

1. Step 1: Understand LTRIM function purpose

   LTRIM removes spaces only from the left side (start) of a string.

2. Step 2: Compare with other trim functions

   Unlike RTRIM (right side) or TRIM (both sides), LTRIM targets only the start.

3. Final Answer:

   Removes spaces only from the start (left side) of the string -> Option D

4. Quick Check:

   LTRIM = left side trim [OK]

Hint: LTRIM trims left side spaces only [OK]

Common Mistakes:

• Confusing LTRIM with RTRIM
• Thinking LTRIM removes spaces from both sides
• Assuming LTRIM removes spaces inside the string

2. Which of the following is the correct syntax to remove trailing spaces from a column named name in SQL?

easy

A. SELECT TRIM(name) FROM table;

B. SELECT LTRIM(name) FROM table;

C. SELECT RTRIM(name) FROM table;

D. SELECT REMOVE_TRAIL(name) FROM table;

Solution

1. Step 1: Identify function to remove trailing spaces

   RTRIM removes spaces from the right (end) side of a string.

2. Step 2: Check syntax correctness

   SELECT RTRIM(name) FROM table; is valid SQL syntax for this purpose.

3. Final Answer:

   SELECT RTRIM(name) FROM table; -> Option C

4. Quick Check:

   RTRIM trims right side spaces [OK]

Hint: RTRIM removes trailing (right) spaces [OK]

Common Mistakes:

• Using LTRIM instead of RTRIM for trailing spaces
• Using TRIM which removes both sides, not just trailing
• Using non-existent function REMOVE_TRAIL

3. Given the string value ' Hello World ', what will the result of SELECT TRIM(' Hello World '); be?

medium

A. 'Hello World'

B. ' Hello World'

C. 'Hello World '

D. 'HelloWorld'

Solution

1. Step 1: Understand TRIM function behavior

   TRIM removes spaces from both the start and end of the string.

2. Step 2: Apply TRIM to the given string

   Spaces before and after 'Hello World' are removed, but spaces inside remain.

3. Final Answer:

   'Hello World' -> Option A

4. Quick Check:

   TRIM removes spaces both sides [OK]

Hint: TRIM removes spaces both sides, not inside [OK]

Common Mistakes:

• Expecting spaces inside the string to be removed
• Confusing TRIM with LTRIM or RTRIM
• Including quotes incorrectly in output

4. You wrote the query SELECT LTRIM(name) FROM users; but it does not remove spaces from the end of the names. What is the issue?

medium

A. The column name should be in quotes for LTRIM to work

B. LTRIM only removes spaces from the start, not the end

C. You should use TRIM to remove spaces only from the end

D. LTRIM removes spaces from both sides, so query is correct

Solution

1. Step 1: Understand LTRIM function limitation

   LTRIM removes spaces only from the left (start) side of a string.

2. Step 2: Identify why trailing spaces remain

   Spaces at the end (right side) are not removed by LTRIM, so they remain.

3. Final Answer:

   LTRIM only removes spaces from the start, not the end -> Option B

4. Quick Check:

   LTRIM trims left side only [OK]

Hint: LTRIM does not remove trailing spaces [OK]

Common Mistakes:

• Assuming LTRIM removes spaces from both sides
• Using quotes incorrectly around column names
• Confusing TRIM and LTRIM functions

5. You have a table products with a column code that sometimes contains spaces at both ends. You want to update the table to remove all leading and trailing spaces from code. Which SQL statement correctly does this?

hard

A. UPDATE products SET code = TRIM(code);

B. UPDATE products SET code = LTRIM(code);

C. UPDATE products SET code = RTRIM(code);

D. UPDATE products SET code = REMOVE_SPACES(code);

Solution

1. Step 1: Understand how to remove spaces from both ends

   TRIM removes spaces from both the start and end of a string in one call.

2. Step 2: Evaluate other options

   LTRIM removes only leading spaces, RTRIM only trailing spaces. Neither alone removes both sides.

3. Step 3: Check for invalid functions

   REMOVE_SPACES is not a valid SQL function.

4. Final Answer:

   UPDATE products SET code = TRIM(code); -> Option A

5. Quick Check:

   TRIM removes both sides spaces [OK]

Hint: Use TRIM to clean both sides in one step [OK]

Common Mistakes:

• Using LTRIM which removes only leading spaces
• Using RTRIM which removes only trailing spaces
• Using invalid function REMOVE_SPACES