Multiple Left Joins in BigQuery - sql

Question

I'm trying to make a currently working SQL query that I have in BigQuery more streamlines and am running into the following issue:
Error: ON clause must be AND of = comparisons of one field name from each table, with all field names prefixed with table name. Consider using Standard SQL .google.com/bigquery/docs/reference/standard-sql/), which allows non-equality JOINs and comparisons involving expressions and residual predicates.
Below is the query that is giving the error above. The first LEFT JOIN works. When I added the second one, right below, I started getting the error. What I'm trying to do is get the human readable own.o.firstname and own.o.lastname values rather than the owner_id value of the deal record (o.properties.hubspot_owner_id.value), but in order to do so I need to join some tables.
I had to use CAST on the ON clause of the second JOIN because the fields are of different types in each table's respective schema. If I don't do that, I get the following error: Error: Join keys o.properties.hubspot_owner_id.value (string) and o.ownerid (int64) have types that cannot be automatically coerced.
The WHERE clause is just a suppression list to not return entries that have been deleted from the database.
SELECT o.*
FROM (
SELECT
o.dealid,
o.properties.dealname.value,
stages.Label,
o.properties.closedate.value,
o.properties.hubspot_owner_id.value,
own.o.firstname,
own.o.lastname,
o.properties.amount.value,
o.properties.createdate.value,
o.properties.pipeline.value,
o.associations.associatedcompanyids,
ROW_NUMBER() OVER (PARTITION BY o.dealid ORDER BY o._sdc_batched_at DESC) as seqnum
FROM [sample-table:hubspot.deals] o
LEFT JOIN [sample-table:hubspot.sales_stages_lookup] stages ON o.properties.dealstage.value = stages.Internal_Value
LEFT JOIN [sample-table:hubspot.owners_reporting] own ON CAST(o.properties.hubspot_owner_id.value AS INTEGER) = CAST(own.o.ownerid AS INTEGER)) o
WHERE o.dealid NOT IN (SELECT objectid FROM [sample-table:hubspot_suppression_list.data] WHERE subscriptiontype = 'deal.deletion') AND seqnum = 1

Answer 1

Use standard SQL in BigQuery instead, which supports expressions as part of the ON clause:
#standardSQL
SELECT o.*
FROM (
SELECT
o.dealid,
o.properties.dealname.value AS dealname_value,
stages.Label,
o.properties.closedate.value AS closedate_value,
o.properties.hubspot_owner_id.value AS hubspot_owner_id_value,
own.o.firstname,
own.o.lastname,
o.properties.amount.value AS amount_value,
o.properties.createdate.value AS createdate_value,
o.properties.pipeline.value AS pipeline_value,
o.associations.associatedcompanyids,
ROW_NUMBER() OVER (PARTITION BY o.dealid ORDER BY o._sdc_batched_at DESC) as seqnum
FROM `sample-table.hubspot.deals` o
LEFT JOIN `sample-table.hubspot.sales_stages_lookup` stages ON o.properties.dealstage.value = stages.Internal_Value
LEFT JOIN `sample-table.hubspot.owners_reporting` own ON CAST(o.properties.hubspot_owner_id.value AS INT64) = CAST(own.o.ownerid AS INT64)) o
WHERE o.dealid NOT IN (SELECT objectid FROM `sample-table.hubspot_suppression_list.data` WHERE subscriptiontype = 'deal.deletion') AND seqnum = 1
For more on the differences between legacy and standard SQL in BigQuery, see the migration guide.