Comments on: Is BIT_LENGTH() useful?

By: PB

PB — Wed, 27 May 2009 08:03:36 +0000

I have never seen bit_length outside of man pages.

By: Ronald Bradford

Ronald Bradford — Tue, 19 May 2009 13:57:12 +0000

Have never used it myself, and have never seen it in use.

By: Shlomi Noach

Shlomi Noach — Tue, 19 May 2009 03:52:23 +0000

@Antony:

LENGTH() returns the number of bytes consumed, not the number of characters.
To get the number of characters, you have CHAR_LENGTH().

With non-ascii characters, and on utf8 charset, it will follow that LENGTH(t) > CHAR_LENGTH(t)

(BTW, BIT_LENGTH is still LENGTH*8 in this case)

By: Antony Curtis

Antony Curtis — Tue, 19 May 2009 02:58:45 +0000

Try using it with a UTF8 string which has some multi-byte characters. LENGTH should return number of characters, BIT_LENGTH would include all the bytes which are used to encode it.
So I would say: Definitely useful.

By: Rob

Rob — Tue, 19 May 2009 01:24:13 +0000

Does it change with a UTF-16 string?

By: Robert Wultsch

Robert Wultsch — Tue, 19 May 2009 00:45:54 +0000

I have never seen bit_length outside of man pages.