How to know a mysql variable is a system or user defined var in mysql command client? -

How to know a mysql variable is a system or user defined var in mysql command client? -

i open mysql client, , type this:

show variables 'var'

it told me variable, didn't properties of variable.

maybe there mysql commands/syntaxs show this.

select @var; works user variable

select @@var; works scheme variables

eg:

select @var1;

select @@sql_mode;

if utilize @@var user defined variables, error.

mysql