Confirming two pieces of data match

[dschemmel]

I have a spreadsheet set up as follows:
Leftmost column contains customer numbers all the way down
Columns 2-20 contain part numbers in row one with blank spaces below. The intent is for an X to be placed in each cell on the table to correspond to that customer number having purchased that part
I.E. Customer 555 is listed on the left in cell A2 and there is an X in cells D2, I2, and K2 to represent customer 555 purchasing those part numbers.

The other sheet (called Data) is set up as follows
Left column customer numbers
Right Column the part number that the customer bought

Each customer number could be repeated numerous times (data has more part numbers than those listed on the sheet) as could each part number.

I was hoping to find a formula for what I am seeking above rather than going through 5,000+ individual data points.

Thank you to anyone who has some advice to offer!

 

[Oscar Cronquist]

	A​	B​	C​	D​	E​	F​	G​	H​	I​	J​	K​	L​
1​	Customer number	PN 1	PN 2	PN 3	PN 4	PN 5	PN 6	PN 7	PN 8		Customer number	Part numbers
2​	1000​										1001​	PN 2,PN 5,PN 8
3​	1001​		X			X			X		1004​	PN 1,PN 6
4​	1002​						X				1010​	PN 2
5​	1003​						X
6​	1004​	X					X
7​	1005​				X
8​	1006​							X	X
9​	1007​		X				X
10​	1008​			X	X
11​	1009​						X		X
12​	1010​		X
13​	1011​					X		X	X

Sheet: Sheet4

Array formula in cell L2:
=TEXTJOIN(",",TRUE,IF(INDEX($B$2:$I$13,MATCH(K2,$A$2:$A$13,0),0)="X",$B$1:$I$1,""))

How to enter an array formula
1. Double click on cell L2
2. Copy / Paste formula to cell L2
3. Press and hold CTRL + SHIFT
4. Press Enter