Incremental refresh - Need details related to "Detect data changes"

[vmakhija]

Hello

In the article below 

https://docs.microsoft.com/en-us/power-bi/service-premium-incremental-refresh#detect-data-changes

under detect data changes, we have following in the Tips section -

Persist only the maximum value of this column at time of refresh, perhaps using a Power Query function.

Can someone tell me what this exactly mean and how this is implemented using power query?

Regards

[Anonymous]

I have the same question. What does this exact statement mean: "Persist only the maximum value of this column at time of refresh, perhaps using a Power Query function."?

I assumed it meant to create another table that pulled the max value in a column and use that as the "Detect Data Changes" column, but I can't use another table so that didn't work.

This tip is found here: https://docs.microsoft.com/en-us/power-bi/admin/service-premium-incremental-refresh

[v-yulgu-msft]

Hi @vmakhija ,

As pointed in above link, the Detect data changes checkbox specify a date/time column, only when the maximum value (lastest date) of this date/time column is changed, for example, latest date changes from 2019/3/28 to 2019/3/29, it refreshes dataset. Otherwise, it keeps the original loaded dataset.

Regards,

Yuliana Gu

[Anonymous]

Hi

I have got a query, What happens if I have a excel file which stores Jan data and I loaded the file and set up incremental refresh, Now the file is overwritten with Feb data. so there is no Jan data in the file. Will Power BI keep the JAN data or will it also overwrite with feb data? I need to keep the old data and load only feb data