Split string into multiple columns with bigquery

Question

I have a table in BigQuery with millions of rows, and I want to split adx_catg_id column to multiple new columns. Please note that the adx_catg_id column contains an arbitra

Answer 1

Check this out...

SELECT  
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){0}([^\s]*)\s?') as Word0,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){1}([^\s]*)\s?') as Word1,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){2}([^\s]*)\s?') as Word2,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){3}([^\s]*)\s?') as Word3,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){4}([^\s]*)\s?') as Word4,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){5}([^\s]*)\s?') as Word5,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){6}([^\s]*)\s?') as Word6, 
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){7}([^\s]*)\s?') as Word7,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){8}([^\s]*)\s?') as Word8,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){9}([^\s]*)\s?') as Word9,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){10}([^\s]*)\s?') as Word10,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){11}([^\s]*)\s?') as Word11,
Regexp_extract(StringToParse,r'^(?:[^\s]*\s){12}([^\s]*)\s?') as Word12,
FROM
(SELECT 'arbitrary number of words separated by space.' as StringToParse)

Or if you want it in reverse order:

SELECT  
Regexp_extract(StringToParse,r'\s?([^\s]*)(?:[^\s]*\s?){1}$') as Word1,
Regexp_extract(StringToParse,r'\s?([^\s]*)(?:[^\s]*\s?){2}$') as Word2,
Regexp_extract(StringToParse,r'\s?([^\s]*)(?:[^\s]*\s?){3}$') as Word3,
Regexp_extract(StringToParse,r'\s?([^\s]*)(?:[^\s]*\s?){4}$') as Word4,
Regexp_extract(StringToParse,r'\s?([^\s]*)(?:[^\s]*\s?){5}$') as Word5,
Regexp_extract(StringToParse,r'\s?([^\s]*)(?:[^\s]*\s?){6}$') as Word6, 
Regexp_extract(StringToParse,r'\s?([^\s]*)(?:[^\s]*\s?){7}$') as Word7,
FROM
(SELECT 'arbitrary number of words separated by space.' as StringToParse)

Its still a fixed number of fields, but coding is simpler and more readable.

Hope this helps

Answer 2

Unfortunately there is no easy SPLIT() today in BigQuery - but it's a good feature request.

I like the answer you developed, I'll experiment more with it. For an alternative approach you can also try https://stackoverflow.com/a/18711812/132438.

The best way to automate this in the meantime, could be automating the query generation outside BigQuery.