MySQL SUBSTR() Function

The SUBSTR() function in MySQL extracts a portion (substring) of a string, starting at a specified position and continuing for a given length. It's a fundamental tool for working with and manipulating text data.

SUBSTR(): Definition and Usage

SUBSTR() allows you to select specific parts of strings. You specify the starting position and the length of the substring you want to extract. MySQL's SUBSTR() function is equivalent to SUBSTRING() and MID().

Understanding Starting Positions

The starting position is 1-based, meaning the first character is at position 1. You can also use negative numbers to count from the end of the string (-1 is the last character).

Syntax

SUBSTR(string, start, length)
--or--
SUBSTR(string FROM start FOR length)
      

Parameter Values

Examples

Extracting a Substring from the Beginning

This extracts three characters starting from position 5 ("Tut").

SELECT SUBSTR("SQL Tutorial", 5, 3) AS ExtractString;
      

Tut
      

Extracting a Substring from a Column

Extracting five characters from the 'CustomerName' column, starting at position 2 (assuming a 'Customers' table with a 'CustomerName' column).

SELECT SUBSTR(CustomerName, 2, 5) AS ExtractString
FROM Customers;
      

ExtractString
-------------
(A substring from each CustomerName will be displayed here)
      

Extracting a Substring from the End

Extracting five characters from the end of the string.

SELECT SUBSTR("SQL Tutorial", -5, 5) AS ExtractString;
      

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