I'm trying to make a query on dataBase Table with ADOQuery by this code

```
begin
    adoquery1.close;
    adoquery1.sql.clear;
    adoquery1.sql.add(SELECT * FROM Table WHERE name=:name and tel=:tel);
    adoquery1.Parameters.ParamByName('name').Value:= edtName.text;
    adoquery1.Parameters.ParamByName('tel').Value:= edtTel.text;
    adoquery1.open;
end;

```

Now, if I set edtName and edtTel the query is return a result  

But what if edtName or edtTel is empty  

the query will return null  

what should I do, to make the query returning the result if one of them or both has a value??

Thanks.