/*COUNT(column_name) will return the number of rows from the column
that are not NULL*/
SELECT COUNT(column_name)
FROM table_name;
/*COUNT(*) will return the number of rows from the table*/
SELECT COUNT(*)
FROM table_name;
/* COUNT() is a function that takes on the name of a clomn as an argument
and counts the number of rows where the column is not null */
SELECT COUNT(column_name)
FROM table_name;