Get published data sources with workbooks

get_published_sources_with_workbook.sql

select * 
  from datasources
  inner join data_connections  on (data_connections.name = datasources.name)
  inner join workbooks on (data_connections.owner_id = workbooks.id)
  where data_connections.dbclass = 'sqlproxy';

This query will return a more reliable match as there could be more than datasource with the same name on your server

select w.id as workbook_id, w.name as workbook_name, d.id as datasource_id, d.name as datasource_name from data_connections dc join workbooks w on dc.owner_id=w.id join datasources d on w.id=d.parent_workbook_id where dc.caption = 'Sample - Superstore' and dc.dbclass = 'sqlproxy' ;