Table Functions and FLATTEN in BigQuery

Question

Is it possible to use FLATTEN and TABLE_QUERY function together?

It looks like the TABLE_QUERY returns only the table name and FLATTEN requires the dataset as well.

FROM Clause:

FROM FLATTEN(TABLE_QUERY(nbr_pcrf, 'table_id CONTAINS "dump_"'), quotas) d

Error:

Query Failed Error: Table name cannot be resolved: dataset name is missing. Job ID: nbr-data-storage:job_44jU_diWnh4tk27UxDxFP-I5Rbg

Answer 1

This is actually a little bit misleading: what is happening is that FLATTEN() with anything that isn't just a table name needs an extra set of parentheses to distinguish the field you're flattening by from a table. In other words, if you do

SELECT ... FROM FLATTEN(TABLE_QUERY(...), foo)

the foo field gets interpreted as a unioned table name (as in SELECT * from bar,foo).

The workaround for this issue is simple: Add another set of parentheses. That is:

SELECT ... FROM 
FLATTEN((TABLE_QUERY(nbr_pcrf, 'table_id CONTAINS "dump_"')), quotas)