Question

i want to ask, how to count date row when data is null using aqua data studio.

For example

select 
convert(varchar(10),dateclosed,103)
from customer
where dateclosed = '(null)'


no.  dateclosed    count(dateclosed)
1     1/1/2001         2
2.    1/1/2001
3.    2/1/2001         1
4.    3/1/2001         1
5.    (null)           4      
6.    (null)         
8.    (null)
9.    (null)
10.    5/1/2001         3
11.    5/1/2001
12.    5/1/2001
13.    6/1/2001         1

Answer 1

The aggregate functions (except for COUNT(*)) ignore the NULL values, so you need to:

• use COUNT(*) (instead of COUNT(expression))
  OR

• convert all the NULL values to some characteristic date:

  SELECT ISNULL(dateclosed, '1900-01-01'), count(ISNULL(dateclosed, '1900-01-01'))
  FROM customer
  GROUP BY ISNULL(dateclosed, '1900-01-01')