Big Query - Transpose arrays into colums

问题

We have a table in Big Query like below.

Input table:

 Name | Interests
 -----+----------
 Bob  | ["a"]
 Sue  | ["a","b"]
 Joe  | ["b","c"]

We want to convert the above table to below format to make it BI/Visualisation friendly.

Target/Required table:

 +------------------+
 | Name | a | b | c |
 +------------------+
 | Bob  | 1 | 0 | 0 |
 | Sue  | 1 | 1 | 0 |
 | Joe  | 0 | 1 | 0 |
 +------------------+

Note: The Interests column is an array datatype. Is this sort of transformation possible in Big Query? If yes, Any reference query?

Thanks in advance!

回答1:

Below is for BigQuery Standard SQL and uses scripting features of BQ

#standardSQL
create temp table ttt as (
  select name, interest 
  from `project.dataset.table`, 
  unnest(interests) interest
);

EXECUTE IMMEDIATE (
  SELECT """
  SELECT name, """ || 
    STRING_AGG("""MAX(IF(interest = '""" || interest || """', 1, 0)) AS """ || interest, ', ') 
  || """
  FROM ttt 
  GROUP BY name
  """
  FROM (
    SELECT DISTINCT interest 
    FROM ttt
    ORDER BY interest
  )
);      

if to apply to sample data from your question - output is

来源：https://stackoverflow.com/questions/64346504/big-query-transpose-arrays-into-colums