What is the difference between the following two sql
statements
select count(*) from <tablename>
select count(col_name) from <tablename>
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Answer Posted / debasis
select count(*) from <tablename> returns the number of rows
in the table.
select count(col_name) from <tablename> return number
values in the column (Ignores null value in the colum). For
example if we execute the following 2 queries then
select count(*) form emp
select count(comm) form emp
The result will be
14
4
| Is This Answer Correct ? | 34 Yes | 7 No |
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