Oracle functions INSTR, SUBSTR, LENGTH, UPPER, LOWER

Usage:
length('snake')
= 5
upper('body')
= BODY
lower('roLLeR')
=roller

subset of a string is substr
substr('thisplace', 5)
= place
substr('thisplace',2,3)
= his

find in a string is instr
instr('thisplace','his')
=2
instr gives this starting position of the searched string in source string.