SQL LEFT

A shortcut for grabbing the first N characters — the same result SUBSTRING(text FROM 1 FOR n) would give, with simpler syntax.

What & Why

LEFT(text, n) returns the first n characters. It's a convenience function for exactly one common slicing pattern — always starting from position 1.

See How It Works

BUSINESS QUESTION

Marketing wants short prefixes and suffixes for campaign-name quality review.

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
  id AS campaign_id,
  name,
  LEFT(name, 4) AS name_prefix,
  RIGHT(name, 4) AS name_suffix
FROM marketing.campaigns
ORDER BY campaign_id;

RESULT — exact output from the displayed Queryflo rows

campaign_id	name	name_prefix	name_suffix
1	Spring Launch	Spri	unch
2	Retention Webinar	Rete	inar
3	Finance Retargeting	Fina	ting
4	Enterprise Search	Ente	arch

LEFT and RIGHT extract four characters from the real campaign names.

Now You Try

Practice this concept

Marketing wants four-character prefixes and suffixes for every campaign name.

Available schema

marketing

Prefix tables with marketing.table_name.

campaign_idnamename_prefixname_suffix

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