Forum Discussion
Data blending using multiple data sources
Hi there,
Although Power BI can do the data blending using multiple data sources, but it need to import them first before the relationship being defined between different data source. This is not practical as some of the data source table can have tens of GB data in size.
For example, I have an excel spreadsheet contain total 100 customers and I need to join them to our data warehouse customer sales revenue table which is in a 20 GB table containing 2 million cusotmer information. Without define the relationship first, I have to import all 2 million customer information into my Power BI desktop before I can join them to the mere 100 customers.
Is there a better way Power BI can handle this? It could be me (new to Power BI) that don't know how to use it.
Thanks.
1 Reply
Yes, you can only import the filtered data because PowerBI does query-folding. So if you join your 2 tables on JoinKind.Inner, this will effectively act as a filter. But watch out: There might still be bugs in it, so you might need a workaround: http://www.thebiccountant.com/2015/09/17/filter-sql-server-queries-with-excel-tables-query-folding-limitations-and-bug-workaround/
