#SQl #difference between the "WHERE" clause and the "HAVING" clause #sql_having #sql_where

What is the difference between the "WHERE" clause and the "HAVING" clause?

1. WHERE clause can be used with a Select, Update and Delete Statement Clause but the HAVING clause can be used only with a Select statement.
2. We can't use an aggregate functions in the WHERE clause unless it is in a sub-query contained in a HAVING clause whereas we can use an aggregate function in the  HAVING clause. We can use a column name in the HAVING clause but the column must be contained in the group by clause.
3.  WHERE is used before the GROUP BY clause whereas a HAVING clause is used to impose a condition on the GROUP Function and is used after the GROUP BY clause in the query.
4.  A WHERE clause applies to each and every row whereas a HAVING clause applies to summarized rows (summarized with GROUP BY).
5.  In the WHERE clause the data that is fetched from memory depending on a condition whereas in HAVING the completed data is first fetched and then separated  depending on the condition.