Question

I am trying to get the maximum ID from a database table and want to show it on win form load.
I am using the following query to get the maximum ID.

SELECT ISNULL(MAX(ID),0)+1  FROM StockMain WHERE VRDATE = '2013-01-30'

Above should have to return the maximum ID of today., e.g if I this statement is excutes for the first time it will return me the Value ‘1’. After saving first record on ID = ‘1’ it should give me MAX(ID) = ‘2’. But it returns me the value 1.

Any suggestion or solutions????

Answer 1

Wild guess… but what data type is VRDATE? Does it include a time component, or is it just a date?

If it includes a time component indicating when you saved the record, it won’t pass the VRDATE = '2013-01-30' check, since this defaults to a time of midnight. Since the times aren’t identical, they are not equal.

Instead, try:

SELECT ISNULL(MAX(ID),0)+1  
FROM StockMain 
WHERE VRDATE BETWEEN '2013-01-30' AND '2013-02-01'

Next question… have you considered using an IDENTITY column instead of managing the ID values manually?