How to implement a more efficient search feature?

Question

In my database there are 3 column which is Name, Age, Gender. In the program, I only want to use 1 search button. When the button is clicked, the program determine which 3 of the textbox has input and search for the right data.

How do you work with the query? For example if Name and Gender has text, the query :

"Select * from table Where (Name = @name) AND (Gender = @gender)"

And when only name is entered, I only query for the name. Must I check textbox by textbox whether there is user input and then write multiple query for each of them? Or is there a better way to do this?

Edit (29/5/16) : I tried doing this another way like this

myCommand = New MySqlCommand("Select * from project_record Where
                       (FloatNo = @floatNo OR FloatNo = 'None') AND 
                       (DevCompanyName = @devCompanyName OR DevCompanyName = 'None') AND 
                       (DevType = @devType OR DevType = 'None') AND 
                       (LotPt = @lotPt OR LotPt = 'None') AND
                       (Mukim = @mukim OR Mukim = 'None') AND
                       (Daerah = @daerah OR Daerah = 'None') AND
                       (Negeri = @negeri OR Negeri = 'None') AND
                       (TempReference = @tempRef OR TempReference = 'None')", sqlConn)

But as you can guess already it will not work efficiently as well because if I only enter input for DevType and leave other textboxes blank, the query will not pull up all the records for DevType only. It will just display as no records.

Answer 1

Select * from table 
Where (Name = @name OR @name is Null) 
  AND (Gender = @gender OR @gender is Null)
 ...

it should be one query