Q:

BigQuery trouble getting substring based on character from the right

I'm having an issue trying to figure out how to parse a string into a substring based on a character that appears multiple times in a string.   For this case I'm trying to get everything to the right of the last '/'. 
Example:
Col          text_string
1            aaa/bbbb/ccccc
2            d/eeee/ff
3            gggg/hh/iiii

What I have so far is:
SELECT
SUBSTR(text_string,[*MY ISSUE*],LENGTH(text_string)) as solution
FROM mytable

To output:
Col          solution
1            ccccc
2            ff
3            iiii

Since GCP doesn't have a right function, what would be the best way to accomplish this goal? 
Thanks

A:

Below is for BigQuery Standard SQL    
#standardSQL
SELECT col, 
  ARRAY_REVERSE(SPLIT(text_string, '/'))[OFFSET(0)] solution
FROM `project.dataset.table`

You can test, play with above using sample data from your question as in below example    
#standardSQL
WITH `project.dataset.table` AS (
  SELECT 1 col, 'aaa/bbbb/ccccc' text_string UNION ALL
  SELECT 2, 'd/eeee/ff' UNION ALL
  SELECT 3, 'gggg/hh/iiii' 
)
SELECT col, 
  ARRAY_REVERSE(SPLIT(text_string, '/'))[OFFSET(0)] solution
FROM `project.dataset.table`
-- ORDER BY col  

with result   
Row col solution     
1   1   ccccc    
2   2   ff   
3   3   iiii     

