SQL: How to select users that have purchased ONLY a certain product? -


say have table looks following

customer     purchases james        basketball james        football alex         basketball

how select customers have purchased basketball? ie alex. or advice.

this 1 way using standard sql;

select customer table1 group customer having count(*) = 1   , max(purchases)='basketball'

an sqlfiddle test with.

if customer may have purchased more 1 basketball, can replace count(*) count(distinct purchases).

if go database specific, more readable option may except or minus, here sql server version;

select customer table1 purchases='basketball' except select customer table1 purchases<>'basketball'

...which same thing latter (may have purchased more 1 basketball) case.


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