CHAR « PL SQL Data Types « Oracle PL/SQL Tutorial

21.2.CHAR
	21.2.1.	CHAR
	21.2.2.	CHAR type variable
	21.2.3.	Compare CHAR and VARVHAR32 variables for equality
	21.2.4.	Constants are compared using blank-padded comparison semantics, so the trailing spaces won't affect the result.
	21.2.5.	Fixed length strings are compared with blank-padded comparison semantic
	21.2.6.	Compare fixed length string and a literal
	21.2.7.	Compare char against varchar, and the trailing spaces do matter.
	21.2.8.	Assigning an empty string to the character variable is exactly the same as assigning NULL to it.