How can I pass the data from combo box to data grid view ?

See more:

C#

SQLite

public UserControl3()
       {
           InitializeComponent();
           SQLiteConnection sqlcon = new SQLiteConnection("Data Source = carRentalDB.db;Version = 3; New = False; Compress = True;");
           SQLiteCommand sqlcmd = new SQLiteCommand("SELECT * FROM Client", sqlcon);
           sqlcon.Open();
           SQLiteDataAdapter sda = new SQLiteDataAdapter(sqlcmd);
           DataSet ds = new DataSet();
           sda.Fill(ds);
           for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
           {
               cbClient.Items.Add(ds.Tables[0].Rows[i][2] + " , " + ds.Tables[0].Rows[i][1]);
           }


           SQLiteConnection con = new SQLiteConnection("Data Source = carRentalDB.db;Version = 3; New = False; Compress = True;");
           SQLiteCommand cmd = new SQLiteCommand("SELECT * FROM Car", con);
           con.Open();
           SQLiteDataAdapter da = new SQLiteDataAdapter(cmd);
           DataSet data = new DataSet();
           da.Fill(data);
           for (int i = 0; i < data.Tables[0].Rows.Count; i++)
           {
               cbCar.Items.Add(data.Tables[0].Rows[i][3] + " - " + data.Tables[0].Rows[i][2] + " - " + data.Tables[0].Rows[i][1]);
           }



       }

this is from my combo box

private void LoadData()
        {
            setConnection();
            sql_con.Open();
            sql_cmd = sql_con.CreateCommand();
            string CommandText = "SELECT Rents.rental_id,Client.lName,Client.fName,Car.car_brand,Car.car_model,Car.plate_number,Rents.rental_date,Rents.return_date,Car.rate,Rents.rental_status From Rents INNER JOIN Client ON Rents.ID = Client.ID INNER JOIN Car ON Rents.car_id = Car.car_id";
            DB = new SQLiteDataAdapter(CommandText, sql_con);
            DS.Reset();
            DB.Fill(DS);
            DT = DS.Tables[0];
            dgvRent.DataSource = DT;

            sql_con.Close();

        }

load data from database

private void cbClient_Click(object sender, EventArgs e)
       {

       }

what is my sql statement here to save and show the data in data grid view to different user control data grid view

What I have tried:

i tried insert into but it did show in my data grid view