SQL LIKE condition to check for integer?
SqlPostgresqlSql Problem Overview
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 with the letter "A":
SELECT * FROM books WHERE title ILIKE "A%"
That's fine for letters, but how do I list all items starting with any number? For what it's worth this is on a Postgres DB.
Sql Solutions
Solution 1 - Sql
That will select (by a regex) every book which has a title starting with a number, is that what you want?
SELECT * FROM books WHERE title ~ '^[0-9]'
if you want integers which start with specific digits, you could use:
SELECT * FROM books WHERE CAST(price AS TEXT) LIKE '123%'
or use (if all your numbers have the same number of digits (a constraint would be useful then))
SELECT * FROM books WHERE price BETWEEN 123000 AND 123999;
Solution 2 - Sql
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
Solution 3 - Sql
If you want to search as string, you can cast to text like this:
SELECT * FROM books WHERE price::TEXT LIKE '123%'
Solution 4 - Sql
Assuming that you're looking for "numbers that start with 7" rather than "strings that start with 7," maybe something like
select * from books where convert(char(32), book_id) like '7%'
Or whatever the Postgres equivalent of convert is.
Solution 5 - Sql
I'm late to the party here, but if you're dealing with integers of a fixed length you can just do integer comparison:
SELECT * FROM books WHERE price > 89999 AND price < 90100;
Solution 6 - Sql
Tested on PostgreSQL 9.5 :
-- only digits
select * from books where title ~ '^[0-9]*$';
or,
select * from books where title SIMILAR TO '[0-9]*';
-- start with digit
select * from books where title ~ '^[0-9]+';
Solution 7 - Sql
Which one of those is indexable?
This one is definitely btree-indexable:
WHERE title >= '0' AND title < ':'
Note that ':' comes after '9' in ASCII.
Solution 8 - Sql
In PostreSQL you can use SIMILAR TO operator (more):
-- only digits
select * from books where title similar to '^[0-9]*$';
-- start with digit
select * from books where title similar to '^[0-9]%$';
Solution 9 - Sql
For those who need to find all values that contain a number (regardless of its position) you can just use:
SELECT * FROM books WHERE title ~ '[0-9]'
(tested with PostgreSQL 13.4)