I'm trying to execute this query
"INSERT INTO Orders Values (" + OrderId.Text + ',' + IDCustTextBox.Text + ',' + CustName.Text + ",SELECT CONVERT(DATE, GETDATE()))"
Since you are using the
INSERT INTO ...VALUES, you don't need a
SELECT. You will use:
"INSERT INTO Orders Values ('" + OrderId.Text + "','" + IDCustTextBox.Text + "','" + CustName.Text + "',GETDATE())"
By the way, you do not need to convert
GETDATE() to a date because it is already a date.