Question

Currently, I have:

public static IList getFilteredEvents(  DateTime Start, DateTime End, string env, string req) {
    string QueryString;
    if( env == "all" ) {
        QueryString = "SELECT * FROM table WHERE date BETWEEN '" + Start + "' AND '" + END + "'";
    } else {
        QueryString = "SELECT * FROM table WHERE date BETWEEN '" + Start + "' AND '" + END + "' AND env='" + env + "'";
    }
}

I am getting the request string by doing passing a data object from the view. In my controller, I get it like this:
string env = Request.QueryString["filter"];

Is there a better way to filter my results instead of having to write multiple queries in an if-elseif chain? How would I achieve this for multiple filters e.g. in the query AND req = '" + req + "';?

Thanks for your help!

Answer 1

You can append ANDs in if-else. For example,

 QueryString = "SELECT * FROM table WHERE date BETWEEN '" + Start + "' AND '" + END + "'";
 if ( env == "all")
 {        
    QueryString  += " AND (env IS NULL OR env=env)"; 
    //if env cannot be null, than you just need  " AND env=env"
 }
 else
 {
     QueryString += "' AND (env='" + env + "')";
 }

And it’s better to use StringBuilder to build a dynamic string;