Suppose I have a database with table A and column A.c1 I do the following

SELECT COUNT(*) FROM A;

and get: 800

but if I do:

SELECT * FROM A;

I get 400 rows returned.

and if I do

SELECT COUNT(c1) FROM A;

I get 400.

So it seems like there are 400 rows of data... so why does COUNT(*) tell me 800??

-e2ka