user variables length

[Entryon Corp., Chief Technical Officer - P. Hasenfratz]

How many Bytes can I save in a user variable?

Because I have the following strategy:

I want to save all PrimaryKeys in a user variable

SELECT @a:=' ';

SELECT @a := CONCAT(@a, ', ', TPrimKey) FROM table WHERE <condition>;

so it is very important to know how many bytes can be stored.

regards

Philipp Hasenfratz