1set session debug="L"; 2select @@global.debug="1"; 3@@global.debug="1" 40 5select @@session.debug; 6@@session.debug 7L 8show global variables like 'debug'; 9Variable_name Value 10debug # 11show session variables like 'debug'; 12Variable_name Value 13debug L 14select * from information_schema.global_variables where variable_name="debug"; 15VARIABLE_NAME VARIABLE_VALUE 16DEBUG # 17select * from information_schema.session_variables where variable_name="debug"; 18VARIABLE_NAME VARIABLE_VALUE 19DEBUG L 20set @@global.debug=1; 21ERROR 42000: Incorrect argument type to variable 'debug' 22set @@global.debug=1.1; 23ERROR 42000: Incorrect argument type to variable 'debug' 24set @@global.debug=1e1; 25ERROR 42000: Incorrect argument type to variable 'debug' 26