Can I Save Data Before it Refreshes?

[RichA08]

Hi All, 

My data refreshes daily and I need to compare it to the previous day. I cannot do incremental refresh as it is not done by date. The data deals in forecasting so it has future dates in it as well. Is there a way to save it into another table or have 2 different datasets refresh at different times?

Sample Dataset: 

Yesterday

Date	Units
1-Oct	123
2-Oct	126
3-Oct	128
4-Oct	131
5-Oct	133
6-Oct	136
7-Oct	138
8-Oct	141
9-Oct	143
10-Oct	146
11-Oct	148
12-Oct	151
13-Oct	153
14-Oct	156
15-Oct	158
16-Oct	161
17-Oct	163
18-Oct	166
19-Oct	168
20-Oct	171
21-Oct	173
22-Oct	176
23-Oct	178
24-Oct	181
25-Oct	183
26-Oct	186
27-Oct	188
28-Oct	191
29-Oct	193
30-Oct	196
31-Oct	198

Today: 

Date	Units
1-Oct	126
2-Oct	129
3-Oct	132
4-Oct	135
5-Oct	138
6-Oct	141
7-Oct	144
8-Oct	147
9-Oct	150
10-Oct	153
11-Oct	156
12-Oct	159
13-Oct	162
14-Oct	165
15-Oct	168
16-Oct	171
17-Oct	174
18-Oct	177
19-Oct	180
20-Oct	183
21-Oct	186
22-Oct	189
23-Oct	192
24-Oct	195
25-Oct	198
26-Oct	201
27-Oct	204
28-Oct	207
29-Oct	210
30-Oct	213
31-Oct	216

[Watson_LIAO]

I guess you can export the data to an excel file in sharepoint with flow (automatically) before refreshing the dataset, and you can re-import the data from that excel to Power BI and set to compare with the latest data.

[v-nmadadi-msft]

Hi @RichA08 

May I check if this issue has been resolved? If not, Please feel free to contact us if you have any further questions.

Thank you

[v-nmadadi-msft]

Hi @RichA08 

I wanted to check if you had the opportunity to review the information provided. Please feel free to contact us if you have any further questions.

Thank you.

[danextian]

Hi @RichA08 

Power BI doesn't store a historical copy of the data so this must be stored somewhere else - an excel file, a database, etc. It reads  whatever is in the datasource upon refresh and overrides the previously existing data. If you are on Fabric, as already mentioned by other users, you may use Dataflow Gen2 instead to pre-process your data instead of doing it in Power Query in Power BI as it has an option to append instead of simply to overwrite.

[v-nmadadi-msft]

Hi @RichA08  ,
Thanks for reaching out to the Microsoft fabric community forum.

A recommended approach is to use Fabric Dataflow Gen2. You can start by creating a dataflow that imports your source data (representing “Today”) and, in Power Query, add a timestamp column using the formula = DateTime.LocalNow(). This column will help you identify the refresh date for each snapshot. Save this dataflow as your “Raw Snapshot Loader” to a Lakehouse table. Next, Refresh the data in your dataflow the updated data should reach a new table in Lakehouse. Once set up, your Power BI dataset can connect to these Lakehouse tables and calculate yesterday-versus-today differences using DAX measures. This method is efficient because it keeps your data versioned within Fabric.

I hope this information helps. Please do let us know if you have any further queries.
Thank you

[Irwan]

hello @RichA08 

as far as i know, power bi does not have memory, so it can not store previous result or dataset.

you need to create a dataset consist of yesterday and today or two table of today and yesterday before imported into power bi.

Thank you.

[samratpbi · Accepted solution]

Hi, it is better to handle this type of scenario in backend itself. May be you can create a snapshot table, which will keep previous day's instance in another table before the data refresh. For every date, you may append into your snapshot table and keep track of your your history data accordingly.

If this helps to resolve your problem then please mark it as solution.

Thanks - Samrat