how large can a table variable be code example

Example: Mysql table variables

CREATE PROCEDURE my_proc () 
BEGIN

CREATE TEMPORARY TABLE TempTable (myid int, myfield varchar(100)); 
INSERT INTO TempTable SELECT tblid, tblfield FROM Table1; 
...
-- Temporary tables in MySQL only exist for the duration of the connection 
-- and only for the connected user, unlike MSSQL where they persist across 
-- sessions and connections.