How to get substring from a sql table? - sql

Question

So I have a column (called account_uri) in a postgres table that looks like this:
/randomCharacters/123456/randomNumbers
I need to query for the substring in the middle, which is a string of characters between two / symbols.
My current attempt looked like this:
SELECT
REVERSE(SUBSTRING(REVERSE([account_uri]),0,CHARINDEX('/',REVERSE(account_uri))))
FROM exp_logs
LIMIT 15
Which selects only the randomNumbers and not the desired numbers.
I tried to build on that idea though and used
(SUBSTRING(REVERSE(SUBSTRING(REVERSE([account_uri]),CHARINDEX('/',REVERSE(account_uri)))),1,CHARINDEX('/',REVERSE(SUBSTRING(REVERSE([account_uri]),CHARINDEX('/',REVERSE(account_uri)))))))
but that only returns a bunch of / symbols and no numbers at all.
If anyone can help me query for this substring, I would be immensely grateful

Answer 1

select
split_part(account_url, '/', 3)
from exp_logs;
works.
http://www.postgresql.org/docs/9.3/static/functions-string.html
Compatibility: 8.3+
Fiddle: http://sqlfiddle.com/#!15/5e931/1

Answer 2

A couple of solutions, sorted by fastest first:
SELECT split_part(account_uri, '/', 3) AS solution_1 -- Neil's solution
,substring(account_uri,'^/.*?/(.*?)/') AS solution_2
,substring(account_uri,'^/[^/]*/(\d*)') AS solution_3
,(string_to_array(account_uri,'/'))[3] AS solution_4
FROM (
VALUES
('/randomCharacters/123456/randomNumbers')
,('/v o,q9063´6qu/24734782/2369872986')
,('/DFJTDZTJ/1/234567')
,('/ ijgtoqu29836UGB /999/29672')
) exp_logs(account_uri);
#Neil's solution proved fastest in a quick test on a table with 30k rows.