SUBSTRING() function in MySQL

SUBSTRING() :
function in MySQL is used to derive substring from any given string .It extracts a string with a specified length, starting from a given location in an input string. The purpose of substring is to return a specific portion of the string.

Syntax :

SUBSTRING(string, start, length)
OR
SUBSTRING(string FROM start FOR length)

Parameters :
This method accepts three-parameter as mentioned above and described below.

• string –
  Input String from which to extract.
• start –
  The starting position. If it is a positive number, this function extracts from the beginning of the string. If it is a negative number, this function extracts from the end of the string.
• length –
  It is optional. It identifies the number of characters to extract. If it is not given The whole string is returned from the starting position.

Example-1 :
Deriving substring from a given string without giving length parameter.

SELECT SUBSTRING("GeeksForGeeks", 3) AS Sub_String;

Output :

Sub_String
eksForGeeks

Example-2 :
Deriving substring from a given string when length parameter is given.

SELECT SUBSTRING("GeeksForGeeks", 3, 8) AS Sub_String; 

Output :

Sub_String
eksForGe

Example-3 :
Deriving substring from a given string when starting position is -ve, i.e: starting from end.

 
SELECT SUBSTRING("GeeksForGeeks", -3 ) AS Sub_String; 

Output :

Sub_String
eks

Example-4 :
Extracting all substring from the text column in a Table.

Table : Student_Details

Student_Id	Student_Name
101	Virat
102	Rohit
103	Rahul
104	Sikhar

SELECT SUBSTRING( Student_Name, 2 ) AS Sub_String FROM Student_Details ;

Output :

Sub_String
irat
ohit
ahul
ikhar