Filtering a table by one of its columns

[MMAKSATULY]

Hi everyone. 

I could not find such a problem on the forum or on the Internet (there are similar problems but there are two or more source tables).

I need any help to filter the source table. In the source table there is a product category and each product has its own key. I would like to filter the source table so that only those products that match the product key with category C remain there. Now I filter separately category C into the table. And then, through the merge, I sort the source into categories A and B. But I can’t combine it all into one table back because of the loop.

I would like all three categories to be in one table and only the same keys as category C products.

Please tell me if it is possible to implement this in power query without cycling error? 

Please see the attachment.  https://drive.google.com/drive/folders/1kmHK3V9MkjHEfyqa7Za8v_G1vXbf4IOK?usp=sharing  Change the location of the excel file in the "filename" parameter.  

Region	Product	Store	Category	Price	Need	Distribution	Product on the way	Month	key
SD	896601218	3520	A	561,48	0	1		01.08.22	3520896601218
SD	896601224	3520	A	214,17	0	1		01.08.22	3520896601224
SD	896601225	3520	A	121,28	0	1		01.08.22	3520896601225
UU	70100319	1205	C	1,59	1	1		01.08.22	120570100319
UU	110101310	1205	C	11,65	1	1		01.08.22	1205110101310
UU	110301017	1205	C	19,57	1	1		01.08.22	1205110301017
KN	30407165	3510	B	0,73	1	1		01.10.22	351030407165
KN	71005023	3510	B	21,07	1	1		01.12.22	351071005023
KN	110001069	3510	B	1,41	1	1		01.11.22	3510110001069

[wdx223_Daniel · Accepted solution]

=let a=Table.SelectRows(PreviousStepName,each [Category]="C"), b=List.Buffer(a[key]) in a&Table.SelectRows(PreviousStepName,each List.Contains(b,[key]))

[JamesRobson]

Hi,

 Not sure I follow are you looking to fitler on 2 seperate criteria at the same time? i.e.

= Table.SelectRows(#"Changed Type", each ([Product Code] = 123) and ([Category] = "C"))

This would show you any line where Product Code = 123 but only if Category = C

If thats not right can you give example of what you are trying to achieve/expect to see.

Thanks,