How to join two tables if the primary keys have two values

[firstnameunknown]

Table A: Primary key is contact id but some cells have two contact id in it.

Table B: Contact id is the primay key. Contact name.

I want to left join Table B into Table A, so the contact names would show in the same column with comma seperared according to the contact id in the Table A.

How can I do it?

[chaorenzhu]

aggr(concat([Contact Email],','),id)

[anat]

Client Product

1 A

1 B

2 B

2 C

2 D

load Client,concat(Product,'-') as NewProduct resident Tablename group by Client;

Can you try like above

[firstnameunknown]

after i added it, after the aggr , lines are all red in errors.

[firstnameunknown]

it has errors

[anat]

Test:

Load * inline [

Client, Product

1 ,A

1,B

2,B

2,C

2,D

];

load Client,concat(Product,'-') as NewProduct resident Test group by Client;

[firstnameunknown]

Hey,  concat name is working but concat emails has errors.

Thank you

[anat]

What error you are getting