Is there any way to use
INSTR('asd','a',1) (which we have for oracle) in Derby databse?
You can use LOCATE for this purpose.
The LOCATE function is used to search for a string within another string. If the desired string is found, LOCATE returns the index at which it is found. If the desired string is not found, LOCATE returns 0.
LOCATE(CharacterExpression, CharacterExpression [, StartPosition] )