Question

How to create table or maybe trigger that doing like this below?

     Date        Data

   2/6/2013         2
   2/6/2013         1
   2/6/2013         3
   2/6/2013         1
   2/6/2013         0

The table at top will alternately as input for next table below, but only the last input will show at table below. The input will alternately from 2 until 0

Just say the input start from 2 – 1 – 3 – 1 – 0, and only 0 will show on table.
How to make the trigger? 0 only data, not something unique. Only the latest input will show on table. Remember the table below triggered table at top to take the data.
I just want every time new input inserted, the data that already existed delete and only the new input will show

  Data
    0

Answer 1

I think you just want a VIEW that shows the latest value.

The following would be the query you’d use for your view…

SELECT TOP 1 Data FROM Table ORDER BY Date DESC

EDIT To do exactly what you want you’d just need a stored procedure for inserting.

-- Copy old value into history
INSERT INTO History SELECT * From Table WHERE yourCondition = True
-- Delete old value
DELETE FROM Table WHERE yourCondition = True
-- Insert new value
INSERT INTO Table VALUES(@Date, @Data)

Now Table will contain only 1 row with the latest value, while History will contain all the old values. This is completely non-standard and irrational, but should be exactly what you want. If you don’t need history you can just remove the first INSERT statement.