select @@global.old; @@global.old 0 select @@session.old; ERROR HY000: Variable 'old' is a GLOBAL variable show global variables like 'old'; Variable_name Value old OFF show session variables like 'old'; Variable_name Value old OFF select * from information_schema.global_variables where variable_name='old'; VARIABLE_NAME VARIABLE_VALUE OLD OFF select * from information_schema.session_variables where variable_name='old'; VARIABLE_NAME VARIABLE_VALUE OLD OFF set global old=1; ERROR HY000: Variable 'old' is a read only variable set session old=1; ERROR HY000: Variable 'old' is a read only variable