How to check if result of request to DB is empty?

[Suliman via Digitalmars-d-learn]

On Saturday, 12 December 2015 at 13:18:12 UTC, anonymous wrote:
> On 12.12.2015 08:44, Suliman wrote:
>>>> string query_string = (`SELECT user, password FROM 
>>>> otest.myusers where
>>>> user LIKE ` ~ `'%` ~ request["username"].to!string ~ `%';`);
>>>
>>> Don't piece queries together without escaping the dynamic 
>>> parts.
>>> Imagine what happens when the user enters an apostrophe in the
>>> username field.
>>
>> Do you mean to wrap:
>>   request["username"].to!string
>> in quotes?
>
> no

What is you suggestion?

P.S. Look like code now work as expected. The problem was with 
rs.next iterator.