SUBSTRING()

Signature

SUBSTRING ( expression , start , length )

Parameters

• expression — A character, binary, text, ntext, or image expression.
• start — An integer or bigint expression that specifies where the returned characters start. (The numbering is 1 based, meaning that the first character in the expression is 1). If *start* is less than 1, the returned expression begins at the first character that is specified in *expression*. In this case, the number of characters that are returned is the largest value of either the sum of *start* + *length* - 1, or 0. If *start* is greater than the number of characters in the value expression, a zero-length expression is returned.
• length — A positive integer or bigint expression that specifies how many characters of the *expression* are returned. If *length* is negative, an error is generated and the statement is terminated. If the sum of *start* and *length* is greater than the number of characters in *expression*, the whole value expression beginning at *start* is returned. If *length* is omitted, all characters from the start position to the end of the expression is returned.

Examples

SELECT SUBSTRING('keyboard', 4, 5) AS part;

part
-----
board

SELECT name,
       SUBSTRING(name, 1, 1) AS Initial,
       SUBSTRING(name, 3, 2) AS ThirdAndFourthCharacters
FROM sys.databases
WHERE database_id < 5;

master|m|st
tempdb|t|mp
model|m|de
msdb|m|db

SELECT SUBSTRING('abcdef', 2, 3) AS x;

bcd

Run against SQL Server 16.0.4265.3 on 2026-09-13. This is the output we got, not the documentation’s.

Available on

• SQL Server 2017 and later
• Azure SQL Database
• Azure SQL Managed Instance
• Azure Synapse Analytics
• Analytics Platform System (PDW)
• Microsoft Fabric warehouse
• Fabric SQL database