oracle 11g sql how MAX() works for varchar

Question

I have these values stored as Varchar :

00
0
NEE-01
LAH-01

how is MAX() function determining which is "more" MAX()? Thanks a lot!

Answer 1

The higher value is determined by the alphabetic sorting based on the collation. L comes before N so, NEE-01 would be the "max" for the given data and LAH-01 would be the "min".

It's the same rule that is applied if you use order by some_varchar_column

As documented in the manual

Character values are compared on the basis of two measures:

• Binary or linguistic sorting

• Blank-padded or nonpadded comparison semantics

And then further down:

In binary comparison, which is the default, Oracle compares character strings according to the concatenated value of the numeric codes of the characters in the database character set . One character is greater than another if it has a greater numeric value than the other in the character set. Oracle considers blanks to be less than any character, which is true in most character sets

^{(Emphasis mine)}

So with the default binary comparison the ASCII values of the characters are taken into account. Which also means that uppercase characters are considered "higher" then lowercase characters.

Answer 2

Due to alphabetic sorting . For eg: 1. A, 2. B ... Z. 26
Higher value is determined.
Eg:
Max(col1) and Col1:

XABC
XYZY

Results :
XYZY
XABC