When do you use WHERE clause and when do you use HAVING clause?

Question

What are the advantage and disadvantages of using a select for update in a cursor Using the "for update clause" and then using useing "update... for current cursor" is a good way to make sure that no one else is changing the rows you are working with.

Answer 1

HAVING clause is used when you want to specify a condition for a group function and it is written after GROUP BY clause. The WHERE clause is used when you want to specify a condition for columns, single row functions except group functions and it is written before GROUP BY clause if it is used.