The Substring function in SQL is used to grab a portion of the stored data. This function is called differently for the different databases:

• MySQL: SUBSTR( ), SUBSTRING( )
• Oracle: SUBSTR( )
• SQL Server: SUBSTRING( )

The most frequent uses are as follows (we will use SUBSTR( ) here):

SUBSTR(str,pos): Select all characters from <str> starting with position <pos>. Note that this syntax is not supported in SQL Server.

SUBSTR(str,pos,len): Starting with the <pos>th character in string <str> and select the next <len> characters.

Assume we have the following table:

Table Geography

Example 1:

SELECT SUBSTR(store_name, 3)
FROM Geography
WHERE store_name = 'Los Angeles';

Result:

's Angeles'

Example 2:

SELECT SUBSTR(store_name,2,4)
FROM Geography
WHERE store_name = 'San Diego';

Result:

'an D'