sql - find similarity of merchant with customers -


i have table in sql server 2012 have columns: user_id , merchant_id

i want find top 5 similar partners each merchant. similarity defined normalized number of overlapping costumers;

i can not find solution problem.

the following query counts number of common customers 2 merchants:

select t.merchantid m1, t2.merchantid m2, count(*) common_customers table t join      table t2      on t.customerid = t2.customerid , t.merchantid <> t2.merchantid group t.merchantid, t2.merchantid;

the following gets 5 based on raw couns:

select * (select t.merchantid m1, t2.merchantid m2, count(*) common_customers,              row_number() on (partition t.merchantid order count(*) desc) seqnum       table t join            table t2            on t.customerid = t2.customerid , t.merchantid <> t2.merchantid       group t.merchantid, t2.merchantid      ) mm seqnum <= 5;

i not know mean "normalized". term "normalized" in statistics not change ordering of values (but result in sum of squares being 1), may want.


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