SQL STRING_AGG

An aggregate function that combines TEXT values across multiple rows into one delimited string — the string-world counterpart to COUNT, SUM, and friends.

What & Why

STRING_AGG(column, delimiter) is an aggregate function — it works with GROUP BY exactly like SUM or COUNT do, but instead of computing a number across a group of rows, it concatenates a text column across them, joined by the given delimiter.

See How It Works

BUSINESS QUESTION

Marketing wants an alphabetized campaign list for every channel.

id	name	channel	spend	start_date	end_date	status	target_segment
1	Spring Launch	google_ads	55000.00	2024-01-15	2024-03-31	active	smb
2	Retention Webinar	email	45000.00	2024-02-10	2024-04-15	active	enterprise
3	Finance Retargeting	linkedin	50000.00	2024-03-12	2024-05-31	active	enterprise
4	Enterprise Search	google_ads	60000.00	2024-04-01	2024-06-30	active	enterprise

EXAMPLE QUERY

SELECT
  channel,
  STRING_AGG(name, ', ' ORDER BY name) AS campaigns
FROM marketing.campaigns
GROUP BY channel
ORDER BY channel;

RESULT — exact output from the displayed Queryflo rows

channel	campaigns
email	Retention Webinar
google_ads	Enterprise Search, Spring Launch
linkedin	Finance Retargeting

STRING_AGG alphabetizes campaign names inside each channel group.

Now You Try

Practice this concept

Marketing wants an alphabetized comma-separated campaign list for every channel.

Available schema

marketing

Prefix tables with marketing.table_name.

channelcampaigns

marketing.campaigns

Column	Type
id	integer
name	text
channel	text
spend	numeric
start_date	date
end_date	date
status	text
target_segment	text
legacy_id	text

query.sql

Intermediate business practice