SQL JOIN USING

A shorthand for ON — usable only when both tables happen to name their shared join column identically.

What & Why

USING (user_id) is a compact alternative to an equality ON clause when both inputs expose the same relationship column. growth.sessions and growth.events both contain user_id, so PostgreSQL can return one shared copy of that key.

See How It Works

BUSINESS QUESTION

Growth links sessions and events through their shared user_id column.

id	user_id	started_at	ended_at	page_views	device
5001	101	2024-01-16 14:20:00+00	2024-01-16 14:52:00+00	8	desktop
5002	102	2024-02-10 11:10:00+00	2024-02-10 11:18:00+00	3	mobile
5003	103	2024-03-13 08:10:00+00	2024-03-13 09:04:00+00	12	desktop
5004	104	2024-04-03 12:00:00+00	NULL	1	tablet
5005	105	2024-04-04 09:00:00+00	2024-04-04 09:21:00+00	7	mobile
5006	106	2024-04-05 10:15:00+00	2024-04-05 10:42:00+00	5	tablet
5007	107	2024-04-06 13:05:00+00	2024-04-06 13:38:00+00	10	desktop

id	user_id	event_name	created_at	properties
1001	101	signup	2024-01-15 09:12:00+00	{"source":"organic"}
1002	101	activated	2024-01-16 14:25:00+00	{"step":"workspace"}
1003	102	signup	2024-02-10 11:08:00+00	{"source":"paid"}
1004	103	report_viewed	2024-03-12 16:40:00+00	{"report":"retention"}

EXAMPLE QUERY

SELECT
  user_id,
  s.id AS session_id,
  e.id AS event_id,
  e.event_name
FROM growth.sessions s
JOIN growth.events e USING (user_id)
ORDER BY user_id, session_id, event_id;

RESULT — exact output from the displayed Queryflo rows

user_id	session_id	event_id	event_name
101	5001	1001	signup
101	5001	1002	activated
102	5002	1003	signup
103	5003	1004	report_viewed

USING(user_id) produces the four real user-level session/event matches.

Now You Try

Practice this concept

Growth wants the first 100 session-event pairs joined through the same-named user_id column.

Available schema

growth

Prefix tables with growth.table_name.

user_idsession_idevent_idevent_name

growth.events

Column	Type
id	bigint
user_id	integer
event_name	text
created_at	timestamp with time zone
properties	jsonb
deprecated_metric	text

growth.sessions

Column	Type
id	bigint
user_id	integer
started_at	timestamp with time zone
ended_at	timestamp with time zone
page_views	integer
device	text
internal_session_score	integer

query.sql

Intermediate business practice