Difference between count (1), count (*), order by 1, 2, 3, and 4

Images and truth

1. Create NULL data;

2. Use the column name to view the results under COUNT.

3. Use 1, 2, 3, 4, 5 * to COUNT and check that all data is the same as all functions.

4 order by 1 do use the first column for sorting

5 order by 2 check that the result is correct

Result:

Count (1) = count (2) = count (3) = count (*);

Count (provcode) <> count (areacode) <> count (statedate) <> count (*);

Order by 1 <> order by 2 <> oreder by 3;

Order by 1 = orderby provcode

Additional results: