Question

query to select customers who bought product a but did not buy products b . (without using sub selects) Table 1 = List of Customers, Table 2 = Products sold to customers (remember if a customer bought product b we want to exclude them from the result) only in one query

Answer 1

安排工作或加入工作将同时进行。

SELECT * FROM Table_1 "t1" JOIN Table_2 "t2" USING (customer) WHERE t1.customer = t2.customer AND product != "b";

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