Count(*) is better in performance than Count(1).

I got this line a Sql book..Can you please explain it?

coun(*)it includes the null values, count(column name) it does not include the null valuesCan you prove this? I cant.
CREATE TABLE test_count(
a VARCHAR2(1)
INSERT INTO test_count (a) VALUES ('#');
INSERT INTO test_count (a) VALUES (NULL);
INSERT INTO test_count (a) VALUES ('~');
INSERT INTO test_count (a) VALUES ('1');
SELECT     COUNT(*) x FROM test_count;
SELECT     COUNT(2) x FROM test_count;gives
table TEST_COUNT created.
1 rows inserted.
1 rows inserted.
1 rows inserted.
1 rows inserted.
X                     
4                     
Y                     
4                      Regards
Marcus

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    Subject :  why is elements better at photomerge than CC- CC does not appear to automatically fill image based on content but elements does when merging a panorama. Also the stitching is visable in CC but almost perfect in elements- why?
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