sql - WHERE clause condition checking for NULL

Question

let's say I have a table with columns ID, Date1 and Date2 where Date2can be NULL. I now want to have an SQL statement that ignores Date2 if it is NULL.

So I need something like that:

SELECT *
FROM
  [myTable]
WHERE
  ID = @someId
  AND Date1 <= GETDATE()
  AND Date2 >= GETDATE() IF Date2 IS NOT NULL

So I want to check if Date2 is not NULL and then compare it with the current date. If it is NULL then I just want to ignore it.
Hope my request is clear and understandable.

Cheers
Simon

Answer 1

AND Date1 <= GETDATE()
AND (Date2 IS NULL OR Date2 >= GETDATE() )

或者

AND Date1 <= GETDATE()
AND COALESCE(Date2, GETDATE()) >= GETDATE()-- which means : if Date2 IS NULL say Date2 = GETDATE()

Answer 2

AND (Date2 >= GETDATE() OR Date2 IS NULL)

Answer 3

试试这个 sql。

    SELECT *
    FROM yourtable
    WHERE ID = @someId
    AND Date1 <= GETDATE()
    AND (Date2 IS NULL
    AND Date2 >= GETDATE());

Answer 4

你可以这样做：

ISNULL(Date2, GETDATE()) >= GETDATE() 

Answer 5

SELECT *
FROM
  [myTable]
WHERE
  ID = @someId
  AND Date1 <= GETDATE()
  AND Date2 NOT IS NULL
  AND Date2 >= GETDATE();