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N036-E2 Tier 3 · Intermediate · easy ecommerce · Brightlane

Return the result of using `CONCAT` to combine `'Hello'`, `', '`, and `'Alex'` into a single string

Part of String Concatenation and Formatting in SQL

The problem

Brightlane's notification system builds greeting messages by combining a salutation and a recipient name.

Write a query to return the result of using CONCAT to combine 'Hello', ', ', and 'Alex' into a single string.

Output:

  • A single row with one column, greeting, containing the concatenated 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
  CONCAT('Hello', ', ', 'Alex') AS greeting

The shape

CONCAT('Hello', ', ', 'Alex') joins its three string arguments end-to-end in the order given and returns 'Hello, Alex'. One function call, one combined string, no separator-management logic required.

Clause by clause

  • SELECT CONCAT('Hello', ', ', 'Alex') AS greeting evaluates the CONCAT call and labels the resulting column greeting. CONCAT is variadic: it accepts any number of arguments and concatenates them left to right into a single string. The literal ', ' is itself one of the arguments, which is how the comma and the space appear between the salutation and the name. There is no FROM because all three values come straight from the prompt as literals.

Why this and not 'Hello' || ', ' || 'Alex'

Both forms return 'Hello, Alex' on this input. CONCAT(a, b, c) reads as one variadic call with the parts in a list, which scales cleanly when there are four, five, or ten components to combine. The || chain reads as a sequence of binary operations and grows visually noisier with each added part. Reach for CONCAT when the operation is naturally a list of pieces rather than a pair.

You practiced CONCAT(...) with multiple arguments — variadic concatenation in one call rather than a chain of || operators.

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