On Monday 11 January 2010 18:22:16 you wrote:
> Hi, Andreas,
Hi,
> I have just checked in a fix to exclude the null values from the
> results. In the example
>
> select avg(c) from null_test where 1=1;
>
> the output would look something like the following
>
> tableSelect -- the result table (1 x 2) for "SELECT avg(c) FROM
> T-null_test WHERE 1=1"
> 2, 3
This is exactly the result i would expect here.
> The results only include three rows; the row where c is null is
> excluded. If you are fine with this way of handling null values,
> please give it a try and let us know if you encounter any problems.
> If you would rather see null values handle properly, i.e., like to
> see the result having 4 rows, have 'select avg(c), count(*)' print out
> something like the following
>
> 2, 3
> , 1
No that's not needed and i don't see a usecase for this.
I made a quick tests against MySQL and the way you just implemented it seems
to be perfectly fine (i assume MySQL is doing SQL compatible stuff when doing
basic SQL ;) ):
CREATE TABLE test (a int,b int);
INSERT INTO test SET a=NULL,b=4;
INSERT INTO test SET a=2,b=3;
SELECT AVG(a),COUNT(a) FROM test;
+--------+----------+
| AVG(a) | COUNT(a) |
+--------+----------+
| 2.0000 | 1 |
+--------+----------+
This is more or less the same you just did in fastbit.
SELECT AVG(a),COUNT(a) FROM test;
+--------+----------+
| AVG(a) | COUNT(a) |
+--------+----------+
| 2.0000 | 1 |
+--------+----------+
This is of course a bit different as COUNT on a specific column doesn't count
the NULLs of this column.
> (note the null value printed on the second row)
> let us know, we will put this feature request on the list of things to do.
>
> John
Kind regards,
Andreas Streichardt
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