How to use set analysis operator(-)

[#1]

Hi to all, I have broblem  that I hope to solve it with your help....

I would like to count the customer who bought specific items and not boutght specific items.

I have table like this.

customer_id, item_id

customer1,item1

customer1,item2

customer2,item1

customer2,item1

customer3,item1

customer3,item2

customer3,item3

customer4,item2

customer4,item3

customer5,item3

customer5,item3

customer6,item1

customer6,item3

And I would like to count the customer who bought item1 and not boutht item2.

The result I want is 2(customer2 and customer6).

I try the following expression, but it doesn't work.

Count({$<item_id={'item1'}> - <item_id={'item2'}>} Distinct customer_id)

Thanks for your help.

Toan

[sunny_talwar · Accepted solution]

May be this:

Count({$<customer_id = p({<item_id = {'item1'}>}) * e({<item_id = {'item2'}>})>} DISTINCT customer_id)

[florentina_doga]

=concat({$<customer_id = p({<item_id = {'item1'}>})

- p({<item_id = {'item2'}>})

>}

DISTINCT customer_id,' ')

[#4]

I try this and it works.

Thank you for your help!

[#5]

I try this and it works.

Thank you for your help!

[oknotsen]

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[#7]

Thank you for your comment.

But I can't find "correct Answer" button near post.

Instead, I find 'Helpful Answers' button, so I flag this.