From: Martijn Tonies
Date: September 11 2006 6:13pm
Subject: Re: Varchar mystery
List-Archive: http://lists.mysql.com/mysql/201771
Message-Id: <006b01c6d5cd$ee6c1330$cd02a8c0@martijnws>
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> I'm using MySQL Linux version 4.1.21 standard.
>
> I have a table with fields of a variety of types, including varchar(255)
and
> text (which might matter). When I do
>
> SELECT MAX(LENGTH(x)) FROM tx;
>
> where x is a varchar(255), I get back 266 as the result of the query!
>
> This isn't listed as one of the silent conversions - varchar(256) would be
> converted to text, but not varchar(255). What's going on?

Well, LENGTH returns the length in bytes, not characters. If you use
characterset in your table/column that uses a multi-byte-per-character
encoding scheme, LENGTH can return more than the number of
characters.

See also CHAR_LENGTH here:
http://dev.mysql.com/doc/refman/5.0/en/string-functions.html


Martijn Tonies
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