Import mode: an explanation about amount of data imported

[laciodrom_80]

Hi all,

I've got a doubt, probably the answer is simple but I'm not sure about it.

I would like to import only a subset of data from a SQL table, I wonder if there is some difference in terms of quantity of data imported between these two scenarios: 

1. Using a SQL statement with an appropriate WHERE clause and import data from this statement;
2. From Power Query, importing all SQL table data and then applying a filter statement. Looking at the Native Queries of each of these two steps I see a select * from table for the first step and a select * from table where... for the second step.

Is there any difference in terms of amount of data imported in the report between these two different approaches

Thanks a lot in advance!

[v-luwang-msft · Accepted solution]

Hi @laciodrom_80 ，

The first connection does not support query folding, which is to import data after querying the database for the data you need to import, and the second supports query folding, which is to import all the data into Power BI and then filter the data you need, that is, the data after where.

refer:https://docs.microsoft.com/en-us/power-query/native-database-query 

https://support.microsoft.com/en-us/office/import-data-from-a-database-using-native-database-query-p...

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Best Regards

Lucien

[laciodrom_80]

@amitchandak ok, but are the two scenarios identical in terms of amount of imported data ?

[amitchandak]

@laciodrom_80 , Based on what I got. That the second option is a power query parameter

In case you plan to control by power query parameter you can change that to increase or decrease the data