Good day to all, master. Please take a look at the image below.

Image1

and this’s my DB sample.

Image2

I want to use a query to check two date ranges (overlaps) but I don’t know how to do that. My idea is to execute this code inside, or after I click the button, Reserve.

private void Btnreserve_Click(object sender, EventArgs e)
{
    // help
}


Please help me to fix my problem, Thank you so much in advance.