how to solve Crystal Reports and Queries?

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ASP.NET

CrystalReports

Hello im having a little problem. Im using the following code trying to fill my crystal report.
As you can see the query is kind of dynamic i mean, the selected dates change and so the query change. When it load the report it comes out empty. I have tried adding the command to the report but i can just add static queries and they wont change when you change the selection, how can i do this.

string query = "SELECT movimientos.fecha, bancos.banco, cuentas.numero_cuenta, movimientos.pago, movimientos.cheque, movimientos.beneficiario, movimientos.referencia, categorias.categoria, conceptos.concepto, movimientos.retiro FROM movimientos INNER JOIN categorias ON movimientos.id_categoria=categorias.id  INNER JOIN conceptos ON movimientos.id_concepto=conceptos.id INNER JOIN cuentas ON movimientos.id_cuenta=cuentas.id INNER JOIN bancos ON movimientos.id_banco=bancos.id WHERE movimientos.id_categoria='" + conexion.categoria + "' AND movimientos.id_concepto='2' AND fecha BETWEEN '" + conexion.fecha1 + "' AND '" + conexion.fecha2 + "'";
     string mySqlString = query;
     myConnection.Open();
     MySqlDataAdapter da = new MySqlDataAdapter(mySqlString, myConnection);
     DataSet ds = new DataSet();
     da.Fill(ds);
     DataTable dt = new DataTable();
     dt = ds.Tables[0];

     ReportDocument rpt = new ReportDocument();
     string reportPath = Server.MapPath("CrystalCompras.rpt");
     rpt.Load(reportPath);
     CrystalReportViewer1.ReportSource = rpt;