GUID обрезается

declare @tt varchar(256)
set @tt='87BD09E2-1993-44B4-9364-071778A3FA1E'
set @tt=ltrim(rtrim(convert(char,@tt)))
print @tt

у меня результат вывода @tt
87BD09E2-1993-44B4-9364-071778

А где конец?
A3FA1E

Начался год свиньи?
Запели соловьи?
Я слушал чуть дыша
Хорошая лапша....

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Цитата из BOL (см. в конце):

Цитата из BOL (см. в конце):

Are character data types of either fixed length or variable length.

char [ ( n ) ]
Fixed-length, non-Unicode character data with a length of n bytes. n must be a value from 1 through 8,000. The storage size is n bytes. The SQL-2003 synonym for char is character.

varchar [ ( n | max ) ]
Variable-length, non-Unicode character data. n can be a value from 1 through 8,000. max indicates that the maximum storage size is 2^31-1 bytes. The storage size is the actual length of data entered + 2 bytes. The data entered can be 0 characters in length. The SQL-2003 synonyms for varchar are char varying or character varying.

Remarks
When n is not specified in a data definition or variable declaration statement, the default length is 1. When n is not specified when using the CAST and CONVERT functions, the default length is 30 (выделено мной).