SQL TRIM Function: Remove Leading/Trailing Spaces (All Databases)

Overview

TRIM removes unwanted characters (usually spaces) from the start and/or end of a string. Essential for data cleaning and input normalization.

MySQL

-- Remove leading and trailing spaces:
SELECT TRIM('  Hello  ');           -- 'Hello'
SELECT LTRIM('  Hello  ');          -- 'Hello  '
SELECT RTRIM('  Hello  ');          -- '  Hello'

-- Remove specific characters:
SELECT TRIM(BOTH '.' FROM '...Hello...');  -- 'Hello'
SELECT TRIM(LEADING '0' FROM '00042');     -- '42'

-- Clean data on insert/update:
UPDATE users SET email = TRIM(LOWER(email));

PostgreSQL

-- Same functions:
SELECT TRIM('  Hello  ');            -- 'Hello'
SELECT LTRIM('  Hello  ');           -- 'Hello  '
SELECT RTRIM('  Hello  ');           -- '  Hello'

-- Remove specific characters:
SELECT TRIM(BOTH '.' FROM '...Hello...');  -- 'Hello'
SELECT TRIM(LEADING '0' FROM '00042');     -- '42'

-- BTRIM (trim from both sides, specific chars):
SELECT BTRIM('xxHelloxx', 'x');  -- 'Hello'

SQL Server

-- TRIM (SQL Server 2017+):
SELECT TRIM('  Hello  ');             -- 'Hello'
SELECT LTRIM('  Hello  ');            -- 'Hello  '
SELECT RTRIM('  Hello  ');            -- '  Hello'

-- Remove specific characters (SQL Server 2017+):
SELECT TRIM('.' FROM '...Hello...');  -- 'Hello'

-- Older versions use LTRIM + RTRIM:
SELECT LTRIM(RTRIM('  Hello  '));

Oracle

-- TRIM:
SELECT TRIM('  Hello  ') FROM DUAL;            -- 'Hello'
SELECT TRIM(LEADING ' ' FROM '  Hello') FROM DUAL;
SELECT TRIM(TRAILING ' ' FROM 'Hello  ') FROM DUAL;

-- Remove specific characters:
SELECT TRIM(BOTH '0' FROM '00042000') FROM DUAL;  -- '42'

-- LTRIM/RTRIM with character set:
SELECT LTRIM('xxxHello', 'x') FROM DUAL;  -- 'Hello'

Skip the Syntax Lookup

Instead of memorizing TRIM syntax for each database, describe what you need in plain English and let AI2SQL generate the correct query.

Frequently Asked Questions