Need Suitable Pure SQL Query

Question

Hi
I have Pure SQL DataBase name of Table as per given Coloumn Name.
User Name StartDate EndDate
Mr.Jack 01/04/2010 05/04/2010
Mr.Perlin 07/04/2010 10/04/2010
Mr.Tinklin 01/05/2010 05/05/2010
Mr.Kerlin 12/04/2010 15/04/2010
Now I am using asp.net Form Using C#...
Name --> TextBox
StartDate -> TextBox
EndDate --> TextBox
Now User enter the Dates after Click Save Button....
Here SQL Query Check Whether the User Dates Clause into Data Base Date's.
For Examble..
User Enter Start Date = 04/04/2010, EndDate =08/04/2010
Now Query it check SQL DataBase, Already 01/04/2010 to 10/04/2010 Available so Dont allow Save.... only allow various dates...
---------------- This is task Condition -------
i am using SQL Query
DECLARE @StartDate DATETIME
DECLARE @EndDate DATETIME
SET @StartDate ='02/04/2010' --// This is User Start Date coming from Text Box
SET @EndDate = '10/04/2010' --// This is User End Date coming from Text Box
IF NOT EXISTS (SELECT PollID FROM Polls WHERE (StartDate<= CAST (CONVERT(VARCHAR,@StartDate,101) AS DATETIME) OR EndDate <= CAST (CONVERT (VARCHAR,@EndDate,101) AS DateTime)) AND STATUS<>'D')
SELECT 'OK ALLLOW'
ELSE
SELECT 'NOT ALLOW'
But it is not working Correctly....
Pls give some correctful query for solve task Condition
By
Riyaz
Edited by: 798225 on Sep 28, 2010 10:37 PM
Edited by: 798225 on Sep 28, 2010 10:52 PM

Answer 1

Now I am developing Polls Application in asp.net
I am using Polls Concept,
DateBase Name : Polls
Fields : PollID          PollName                           StartDate                                     EndDate                     UserID
In Asp.Form Having
User Name :  TextBox
PollName: TextBox
StartDate: TextBox
EndDate: TextBox
Submit - Button
Task Details
Whenever User Click after fillup all data's... then SQL Query Check
if StartDate or EndDate is exists in Between DataBase Date's.....
Condition true means dont allow save.. else Save.....
Examble:
PollID PollName StartDate EndDate UserName
01 Sample 23/09/2010 26/09/2010 Klit
02 Sample 2 29/09/2010 30/09/2010 Jack
Now User given follwing details and click Submit,
User Name : James
PollName: Test
StartDate: 22/09/2010
EndDate: 27/09/2010
Submit - Button
Here User StartDate: 22/09/2010 , EndDate: 27/09/2010
SQL Query Check ,
Condtion 1 : Those dates are avilable in Datebase???
Result: Yes
Because, Sample Poll date is 23/09/2010 to 26/09/2010, here Start Date is Not Exists, But End Date Exists.
So dnt allow Save Operation....
Now User Again given follwing details and click Submit,
User Name : James
PollName: Test
StartDate: 27/09/2010
EndDate: 28/09/2010
Submit - Button
Here User StartDate: 27/09/2010 , EndDate: 28/09/2010
SQL Query Again Check ,
Condtion 1 : Those dates are avilable in Datebase???
Result: No
Because, Sample Poll date is 23/09/2010 to 26/09/2010,
Sample1 Poll Date is 29/09/2010 to 30/09/2010
here Start Date is Not Exists, But End Date Not Exists.
So Allow Save Operation....
This a My Task....
Could You give SQL Query for help to Check given condition??
regd
Riayz
Edited by: Riyaz on Sep 30, 2010 1:08 AM