how to bring in data from a database by using data in another database

[Manohargon]

I have 2 different database. the table in first database has 12 million records and table in second database has 0.6 million records.

I need to bring in 0.6 million records from first database using a key column from the second database. how do i do this. I used a custom function and it is taking lot of time.

i also need to compare the data from both database and build a report to show the differences. 

Please help with some options

[Manohargon]

Thanks for you reply.

I don't want to bring in all 12 million records as it consumes time and the pbix file is limited to 1 gb.

i used custom function to bring in only 0.6 million record out of 12 million records but it is consuming time.

Is there an alternate solution to bring in only 0.6 million records or how to reduce the time that custom function is taking to fetch the data

[zenisekd]

I would simply use power query - use import to pull the tables from both databases and then use merge (depending on the needs I would pick the join I need) by the key column. Make sure you are pulling only the columns and rows you need before the merge.