SELECT ... FROM typeofcall , report2 This is NOT a full join, this is a cross join, yet another join type not at all mentioned. Full join: http://www.w3schools.com/sql/sql_join_full.asp A cross join is even less often used than a full join, as it combines every row of one...
SELECTvend_name, prod_name, prod_priceFROMvendors, productsORDERBYvend_name, prod_name; SELECTvend_name, prod_name, prod_priceFROMvendorsINNERJOINproductsONvendors.vend_id=products.vend_id; 虽然默认就是 inner join (看这个),但是最好还是用 INNER JOIN ON 语句,这样你就再也不会忘记 JOIN 的类型...