COUNT « Aggregate Functions « Oracle PL/SQL Tutorial

12.3.COUNT
	12.3.1.	COUNT(x) gets the number of rows returned by a query.
	12.3.2.	Passes ROWID to COUNT() and gets the number of rows
	12.3.3.	COUNT() with null
	12.3.4.	Using an aggregate with the GROUP BY clause to count by city
	12.3.5.	COUNT(1) from a table
	12.3.6.	Count column with table alias
	12.3.7.	Count distinct column value
	12.3.8.	Compare the difference between count(*) and count(distinct course)
	12.3.9.	Count employees in the same department

	12.3.10.	JOIN with AND and aggregate function
	12.3.11.	count(*) - count(onhand)
	12.3.12.	count(*) vs count(column name)
	12.3.13.	Count all employees by even/odd employee id
	12.3.14.	Count date field value, and calculation