Group data according to a lookup table and select the first non-null value

[Syndicate_Admin]

Hello all,

I am trying to solve the following problem in in Power Bi using Power Query. I have found some stuff around this forum but it is not exactly what i need to do, and i am not so expert to figure out by myself.

I have a lookup table like this:

NAME	ID
aaa	id12
aaa	id34
aaa	id23
bbb	id15
bbb	id25
ccc	id67
ccc	id54
ccc	id33
ddd	id20
ddd	id65
ddd	id78

And a Raw Data Table like this:

(The very first row is not part of table. I added it for the sake of clarity)

		#aaa	#aaa	#aaa	#bbb	#bbb	#ccc	#ccc	#ccc	#ddd	#ddd	#ddd
timestamp	object	id12	id34	id23	id15	id25	id67	id54	id33	id20	id65	id78
13/04/2022 13:54	L1	3202			4841			5548				7142
12/04/2022 04:22	L3	2541			8963			5047				7596
11/04/2022 06:47	N6		6165		2834	8034			3569	7984
10/04/2022 18:42	M4	2586		8555		6135	9539			6527
09/04/2022 11:11	M4	1290		9642		9944	5077			3355
08/04/2022 12:11	L2	8060			5835			8539				6354
07/04/2022 14:00	N6		6910		3955	3967			2868	9192
06/04/2022 13:56	N6		2370		3002	4200			7257	8699
05/04/2022 01:11	L1	7230			4520			1606				3594
04/04/2022 08:37	M4	3205		5283		8986	8943			5553
03/04/2022 23:37	L1	4740			6182			9407				6881
02/04/2022 10:00	L2	1445			6379			1282				7989
01/04/2022 14:37	L1	9878			3534			7907				2312

I would like to create an output table like the following:

timestamp	object	aaa	bbb	ccc	ddd
13/04/2022 13:54	L1	3202	4841	5548	7142
12/04/2022 04:22	L3	2541	8963	5047	7596
11/04/2022 06:47	N6	6165	2834	3569	7984
10/04/2022 18:42	M4	2586	6135	9539	6527
09/04/2022 11:11	M4	1290	9944	5077	3355
08/04/2022 12:11	L2	8060	5835	8539	6354
07/04/2022 14:00	N6	6910	3955	2868	9192
06/04/2022 13:56	N6	2370	3002	7257	8699
05/04/2022 01:11	L1	7230	4520	1606	3594
04/04/2022 08:37	M4	3205	8986	8943	5553
03/04/2022 23:37	L1	4740	6182	9407	6881
02/04/2022 10:00	L2	1445	6379	1282	7989
01/04/2022 14:37	L1	9878	3534	7907	2312

So that, it reprocess the raw data table replacing the "idxx" columns with "name" according to the lookup table and assign for that "name" only one value. The value must be the first non-null value of that "name" group for each row

Hope that i have been clear enough. The output example should help to better understand what i am trying to do here

Please note that the Lookup table and the Raw data table are both queried from MySQL database, so if necessary i could rearrange those two tables when loading them in power bi.

Thank you

[Syndicate_Admin]

See the working here - Open a blank query - Home - Advanced Editor - Remove everything from there and paste the below code to test (later on when you use the query on your dataset, you will have to change the source appropriately. If you have columns other than these, then delete Changed type step and do a Changed type for complete table from UI again)

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("VZPZjQQhDERTWfX3SINPbGLo3QRGk38ay2EakBCX4FG2i8/n4jfQGxPiD1ARvl7XDbWjulWH0dgYnoUI27OoLQPj9X11Eg4SF2yXb6odynbXXGmBEucDJK4TBAOkpR/503FCQWXM0KhJtdSH0UjUG8Zt7gUsRXxWuMn65S7LAmoiMvHUZi7kD1QF80HzgEEBmDBAT+OQK0fa3Jl7kHkFSTSfCpgFDAfsxh6TppUjI3kWtgtr2qjWa4BygLiktCfMIVjk/WlyXXLQtFXSwfFQpcsPusGQ8oSlbg7GtJRmlEY2dT9gErCIEPpRWvdYcC1Ak+4RkviMkAfHCuWZ9urRSI5UP0yH9bqa82Y0ETo0heGRBqyL4sxLh4It9zunw6dqBgEKv0Maae/1A+ZVMqW8Sga4UYdTfXr0qd9S5JbXRyPZnJ79VIQE9Qt+/wE=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [timestamp = _t, object = _t, id12 = _t, id34 = _t, id23 = _t, id15 = _t, id25 = _t, id67 = _t, id54 = _t, id33 = _t, id20 = _t, id65 = _t, id78 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"timestamp", type datetime}, {"object", type text}, {"id12", Int64.Type}, {"id34", Int64.Type}, {"id23", Int64.Type}, {"id15", Int64.Type}, {"id25", Int64.Type}, {"id67", Int64.Type}, {"id54", Int64.Type}, {"id33", Int64.Type}, {"id20", Int64.Type}, {"id65", Int64.Type}, {"id78", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Added Index", {"timestamp", "object", "Index"}, "Attribute", "Value"),
    #"Added Custom" = Table.AddColumn(#"Unpivoted Other Columns", "Custom", each Table1{[ID=[Attribute]]}[NAME]),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Attribute"}),
    #"Pivoted Column" = Table.Pivot(#"Removed Columns", List.Distinct(#"Removed Columns"[Custom]), "Custom", "Value", List.Sum),
    #"Sorted Rows" = Table.Sort(#"Pivoted Column",{{"Index", Order.Ascending}}),
    #"Removed Columns1" = Table.RemoveColumns(#"Sorted Rows",{"Index"})
in
    #"Removed Columns1"

Test code for Table1

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WSkxMVNJRykwxNFKK1UFwjU1QuEbGYG5SUhJEsSkK1wjCTU5OBnPNzFG4piYoXGOIUSkpKRC9BihcM1MUrrmFUmwsAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [NAME = _t, ID = _t])
in
    Source

[Syndicate_Admin]

Thank you very much Vijay_A_Verma!

It seems exactly what i was looking for. I am going to try it on my actual data (that are a bit different) and let you know!

But it looks like its working, so i am not expecting surprises.

Thanks again!

[Syndicate_Admin]

Hello Vijay_A_Verma,

Sorry to bug you again, but i was too excited for the quick solution (i have been on it for 1 entire week) that i didn't notice that it does not cover all cases.

There are some cases in the raw data table with more the one value for each id group, for example:

#aaa

#aaa

#aaa

#bbb

#bbb

#ccc

#ccc

#ccc

#ddd

#ddd

#ddd

timestamp

object

id12

id34

id23

id15

id25

id67

id54

id33

id20

id65

id78

10/04/2022 18:42

M4

2586

8555

6135

9539

6527

09/04/2022 11:11

M4

1290

9642

9944

5077

3355

Here for the "aaa" there are 2 values, and i would like to take only the first non-null value, so i am expecting 

timestamp	object	aaa	bbb	ccc	ddd
10/04/2022 18:42	M4	2586	6135	9539	6527
09/04/2022 11:11	M4	1290	9944	5077	3355

While with your solutions, it is adding all the "idxx" of same group:

Do you know how it could be possible to manage this cases as well?

Thank you!

[Syndicate_Admin]

@Vijay_A_Verma 

Never mind, i figured it out

I added a "remove duplicate" steps, selecting the "custom" and the "timestamp" (in order to have an unique releation for each row). Is not so elegant as solution but it does the trick!

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("VZPbjcQgDEVbWeV7pMFPbGrIbgOj6b+N5WECSIgAgcO1ffl8Ln4DvTEh/gAV4et13VA7qkv1MxobwzMRYXsmtWVgvL6vTsJB4oLt8E21Q9nOmistUOJ8gMR1gmCAtPQtfzp2KKiMERo1qZb6ZzQS9YZxm2sBSxGfFW6yfrnLsoCaiEw8tZEL+QNVwXzQPGBQACYM0NPY5MqRNnfmHmReQRLNqwJmAcMBu7HHpGnlyEieie3Cmjaq9RqgHCAuKe0JcwgWeb+aXJccNG2VdHA8VOnyg24wpDxhqZuDMS2lGaWRTd0PmAQsIoQ9ABZcANCk+08Sn9HxYFihPFNe/RmJkeqF6a5eU3PeTCZCh54wO9KAdUGceelQsOV853R4VM0gQOF1SCPlvXbAvMqllFe5ADfqcKlPfz61W4rc8npkJJvLs5+KkKA+v+8/", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [timestamp = _t, object = _t, id12 = _t, id34 = _t, id23 = _t, id15 = _t, id25 = _t, id67 = _t, id54 = _t, id33 = _t, id20 = _t, id65 = _t, id78 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"timestamp", type datetime}, {"object", type text}, {"id12", Int64.Type}, {"id34", Int64.Type}, {"id23", Int64.Type}, {"id15", Int64.Type}, {"id25", Int64.Type}, {"id67", Int64.Type}, {"id54", Int64.Type}, {"id33", Int64.Type}, {"id20", Int64.Type}, {"id65", Int64.Type}, {"id78", Int64.Type}}),
    #"Added Index" = Table.AddIndexColumn(#"Changed Type", "Index", 0, 1, Int64.Type),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Added Index", {"timestamp", "object", "Index"}, "Attribute", "Value"),
    #"Added Custom" = Table.AddColumn(#"Unpivoted Other Columns", "Custom", each Table1{[ID=[Attribute]]}[NAME]),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Attribute"}),
    #"Removed Duplicates" = Table.Distinct(#"Removed Columns", {"Custom", "timestamp"}),
    #"Pivoted Column" = Table.Pivot(#"Removed Duplicates", List.Distinct(#"Removed Duplicates"[Custom]), "Custom", "Value", List.Sum),
    #"Sorted Rows" = Table.Sort(#"Pivoted Column",{{"Index", Order.Ascending}}),
    #"Removed Columns1" = Table.RemoveColumns(#"Sorted Rows",{"Index"})
in
    #"Removed Columns1"

 Thanks!