select length(encrypt('foo', 'ff')) <> 0;
length(encrypt('foo', 'ff')) <> 0
1
select old_password('test'), password('test');
old_password('test')	password('test')
378b243e220ca493	378b243e220ca493
select length(encrypt('test')), encrypt('test','aa');
length(encrypt('test'))	encrypt('test','aa')
13	aaqPiZY5xR5l.
drop table if exists t1;
create table t1 (name varchar(50), pw varchar(16));
insert into t1 values ('tom', password('my_pass'));
set @pass='my_pass';
select name from t1 where name='tom' and pw=password(@pass);
name
tom
select name from t1 where name='tom' and pw=password(@undefined);
name
drop table t1;