下图展示了 LEFT JOIN、RIGHT JOIN、INNER JOIN、OUTER JOIN 相关的 7 种用法。 具体分解如下: 1、INNER JOIN(内连接) SELECT <select_list> FROM Table_A AINNER JOIN Table_B BON A.Key = B.Key 2、LEFT JOIN(左连接) SELECT <select_list>FROM Table_A ALEFT JOIN Table_B BON A.Key = B.Key 3、RIGHT JOIN(右连接) SELECT <select_list>FROM Table_A ARIGHT JOIN Table_B BON A.Key = B.Key 4、OUTER JOIN(外连接) SELECT <select_list>FROM Table_A AFULL OUTER JOIN Table_B BON A.Key = B.Key 5、LEFT JOIN EXCLUDING INNER JOIN(左连接-内连接) SELECT <select_list> FROM Table_A ALEFT JOIN Table_B BON A.Key = B.KeyWHERE B.Key IS NULL 6.RIGHT JOIN EXCLUDING INNER JOIN(右连接-内连接) SELECT <select_list>FROM Table_A ARIGHT JOIN Table_B BON A.Key = B.KeyWHERE A.Key IS NULL 7、OUTER JOIN EXCLUDING INNER JOIN(外连接-内连接) SELECT <select_list>FROM Table_A AFULL OUTER JOIN Table_B BON A.Key = B.KeyWHERE A.Key IS NULL OR B.Key IS NULL |
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