的信息。
方式一(通用型):SELECT ... FROM ... WHERESELECT e.last_name,e.department_id,d.department_nameFROM employees e,departments dwhere e.department_id = d.department_id方式二：SELECT ... FROM ... NATURAL JOIN ...有局限性：會自動連接兩個表中相同的列(可能有多個:department_id和manager_id)SELECT last_name,department_id,department_nameFROM employeesNATURAL JOIN departments方式三：SELECT ... JOIN ... USING ...有局限性：好于方式二，但若多表的連接列列名不同，此法不合適SELECT last_name,department_id,department_nameFROM employeesJOIN departmentsUSING(department_id)方式四：SELECT ... FROM ... JOIN ... ON ...常用方式，較方式一，更易實現外聯接(左、右、滿)SELECT last_name,e.department_id,department_nameFROM employees eJOIN departments dON e.department_id = d.department_id--內連接 1） --等值連接 --不等值連接 2） --非自連接 --自連接--外連接 --左外連接、右外連接、滿外連接新聞熱點
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