Joining tables from different locations in Bigquery
You can't join two tables in different data set which are in different locations. As an alternative solution, you can copy datasets between regions using BigQuery Data Transfer Service. Here is the documentation link Copying Datasets:
bq mk --transfer_config \
      --project_id=myproject \
      --data_source=cross_region_copy \
      --target_dataset=dataset_us \
      --display_name='Copy Dataset' \
      --params='{&quot;source_dataset_id&quot;:&quot;dataset_eu&quot;,&quot;source_project_id&quot;:&quot;myproject&quot;}'