Convert Long table to wide table in BigQuery

问题

I have a BigQuery table like this:

Required Output is :

Note : The keys in Extended_property_key column are not fixed, it keeps on adding frequently. Hence the columns in Output will also keep on adding.

I need to build a Bigquery which can handle dynamic adding of columns in output query along with pivoting.

回答1:

Below is for BigQuery Standard SQL

EXECUTE IMMEDIATE '''
SELECT account_id, ''' || (
  SELECT STRING_AGG(DISTINCT "MAX(IF(Extended_property_key = '" || Extended_property_key || "', Extended_property_value, NULL)) AS " || Extended_property_key)
  FROM `project.dataset.table`
) || '''  
FROM `project.dataset.table`
GROUP BY 1
ORDER BY 1
'''   

If applied to sample data in your question - output is

Row account_id  Key1    Key2    Key3     
1   1           Value1  null    null     
2   7           null    Value2  Value3   

回答2:

Try:

CALL fhoffa.x.pivot(
  'p.d.t1' # source table
  , 'p.d.t2' # destination table
  , ['ACCOUNT_ID'] # row_ids
  , 'EXTENDED_PROPERTY_KEY' # pivot_col_name
  , 'EXTENDED_PROPERTY_VALUE' # pivot_col_value
  , 30 # max_columns
  , 'ANY_VALUE' # aggregation
  , '' # optional_limit
);

More details on how to pivot:

• https://towardsdatascience.com/easy-pivot-in-bigquery-one-step-5a1f13c6c710

来源：https://stackoverflow.com/questions/62562149/parametrized-table-name-and-column-name-in-standard-sql-bigquery