Difference between a HAVING CLAUSE and a WHERE CLAUSE?

Both HAVING and WHERE clause used for specifying the search condition in SQL queries.

HAVING can be used only with the SELECT statement. HAVING is typically used in a GROUP BY clause. When GROUP BY is not used, HAVING behaves like a WHERE clause. Having Clause is basically used only with the GROUP BY function in a query.

WHERE Clause can be used for specifying the search criteria in SELECT, DELETE, UPDATE statements.

we can't use Having with out GROUP BY function

Good.

we can use HAVING without GROUP BY().