[Database] mybatis frame order by the use of dynamic parameters and # $ {} {} and difference

simply say

# {} Is pre-compiled, it is safe

$ {} It is not pre-compiled, taking only the value of a variable, non-secure, there sql injection.

If you use the mapper file

ORDER BY #{columnName}

Sql statement will lead to the final argument to pay more quotes, for example,

select * from test order by 'update_time';

To use this

ORDER BY ${columnName}

But note that this will lead to a potential SQL injection attacks, so you need to check yourself and escape