我正在预订系统，我希望在进行新预订时获取DataGridView的房间详细信息。房间详细信息位于一个名为service的表中，预订详细信息位于items_reserved表中。在每次预订时，我都需要检查日期和时间。
如果我只考虑日期，以下查询效果很好：
"SELECT * FROM Service " &
"WHERE Service_Type_ID= '" & txtBoxSerType.Text & "'" &
" AND Service_ID NOT IN (" &
" SELECT Service_ID FROM Items_Reserved" &
" WHERE Date_In <= '" & DateTimePickerDateOut.Text & "'" &
" AND Date_Out >= '" & DatePickerDateIn.Text & "'" &
" AND Status Is Null" &
" )"
但我还需要检查时间限制。以下查询是我尝试过的，但遗憾的是它无效：
"SELECT * FROM Service " &
"WHERE Service_Type_ID= '" & txtBoxSerType.Text & "'" &
" AND Service_ID NOT IN (" &
" SELECT Service_ID FROM Items_Reserved" &
" WHERE Date_In <= '" & DateTimePickerDateOut.Text & "'" &
" AND Date_Out >= '" & DatePickerDateIn.Text & "'" &
" AND Status Is Null" &
" AND Service_ID Not In (" &
" SELECT Service_ID FROM Items_Reserved" &
" WHERE Date_In = '" & DateTimePickerDateOut.Text & "'" &
" AND Time_In <= '" & DateTimePickerTimeOut.Text & "'" &
" AND Status Is Null" &
" AND Service_ID Not In (" &
" SELECT Service_ID FROM Items_Reserved" &
" WHERE Date_Out = '" & DatePickerDateIn.Text & "'" &
" AND Time_Out >='" & DateTimePickerTimeIn.Text & "'" &
" AND Status Is Null" &
" )" &
" )" &
" )"
例如，假设Room1有一个预留位置：
DateIn = 11/15/2015和DateOut = 11/17/2015和TimeIn = 12:00和TimeOut = 14:00 当我使用给出的第二个查询时，输入新的预订详细信息以检查可用房间：
DateIn = 11/17/2015和DateOut = 11/20/2015 TimeIn = 18:00和TimeOut = 08:00 理想情况下，Room1应显示为可用。