SQL LIKE condition to check for integer?

Question

I am using a set of SQL LIKE conditions to go through the alphabet and list all items beginning with the appropriate letter, e.g. to get all books where the title starts wit

Answer 1

In PostreSQL you can use SIMILAR TO operator (more):

-- only digits
select * from books where title similar to '^[0-9]*$';
-- start with digit
select * from books where title similar to '^[0-9]%$';

Answer 2

PostgreSQL supports regular expressions matching.

So, your example would look like

SELECT * FROM books WHERE title ~ '^\d+ ?' 

This will match a title starting with one or more digits and an optional space