I am writing a query, where I am using the division operator. For some reason I can't get it to work properly, and I can't see why.
pol = pi allergen (sigma allergy_type = 'pollen' (allergies))
tmp = (patient_allergies/pol)
tmp
The above is my query. In pol I am retrieving all allergens, who has the allergy type pollen. This gives me a 1 column, two rows table, which content is the two allergens who has allergy_type pollen. tmp: Patient_allergies is a 2 column, 23 row table. The first column is allergens, second column is ssn for the people with those allergens. What I am trying to do, is to get everyone in patient_allergies, who has the two allergens I found in pol. I'm pretty sure I need to division operator for this, but it returns an empty list, which is incorrect for what I am trying to do.
EDIT: I am using this relational algebra calc, provided by our university: dbis-uibk.github.io/relax/calc/local/uibk/local/0 There is a division operator with another symbol, but yields the same result