substring function

The substring function extracts a string from a given string according to a given numeric starting position and a given numeric substring length.
returnvalue substring (source, position [, substring_length] )

source ::= any*
position ::= integer*
substring_length ::= integer*
returnvalue ::= string
Example: Fetch the first three characters from the routing details of a passenger with ticket number 1762376407826.
SELECT substring(bag.baginfo.routing,0,3) AS Source 
FROM baggageInfo bag 
WHERE ticketNo=1762376407826
Output:
{"Source":"JFK"}