When You Filter Makes a Difference
You now know two ways to filter your final result set: WHERE and HAVING. You also know that there are certain limitations on the predicates you can use within a search condition in a HAVING clause. In some cases, however, you have the choice of placing a predicate in either clause. Let’s take a look at the reasons for putting your filter in the WHERE clause instead of the HAVING clause.
Should You Filter in WHERE or in HAVING?
You learned in Chapter 6 about five major types of predicates you can build to filter the rows returned by the FROM clause of your request. These are comparison (=, <>, <, >, >=, <=), range (BETWEEN), set membership (IN), pattern match (LIKE), and Null (IS NULL). In Chapter 11, we expanded ...
Get SQL Queries for Mere Mortals: A Hands-On Guide to Data Manipulation in SQL, Second Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
