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N035-E3 Tier 3 · Intermediate · easy ecommerce · Brightlane

Return the trimmed value of the string `' [email protected] '`

Part of String Functions (LENGTH, UPPER, LOWER, TRIM, SUBSTRING) in SQL

The problem

Brightlane's data cleaning step removes leading and trailing whitespace from user-submitted email addresses before they are stored.

Write a query to return the trimmed value of the string ' [email protected] '.

Output:

  • A single row with one column, clean_email, containing the trimmed string.
Schema · ecommerce 5 tables
categories
id integer
name text
parent_id? integer
products
id integer
name text
category_id integer
price numeric
stock_qty integer
attributes? jsonb
order_items
id integer
order_id integer
product_id integer
quantity integer
unit_price numeric
customers
id integer
name text
email text
city? text
country text
created_at timestamptz
is_active boolean
orders
id integer
customer_id integer
ordered_at timestamptz
status text
total_amount numeric
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Solution query
SELECT
  TRIM('   [email protected]   ') AS clean_email

The shape

TRIM(' [email protected] ') removes the three leading and three trailing spaces and returns '[email protected]'. The default TRIM strips spaces from both ends, which is exactly the cleanup the email-storage step needs.

Clause by clause

  • SELECT TRIM(' [email protected] ') AS clean_email runs the function against the padded literal and labels the result clean_email. With no characters argument and no side specified, TRIM defaults to stripping spaces from both the left and the right until it hits a non-space character on each side. The interior of the string is untouched, so the email itself comes through intact.
  • There is no FROM because the value being cleaned is the literal embedded in the SELECT. One input, one output, no table needed.

Why this and not a per-side trim

A user-submitted email could carry whitespace on either end, and TRIM with no side argument handles both at once. Reaching for LTRIM or RTRIM here would only strip one side and leave the other padding in place, which would fail the next equality check against a clean address. The default both-sides behavior is what the storage step depends on.

You practiced TRIM(...) — strip leading and trailing spaces by default; the standard preprocessing step for inbound text values.

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