\ud310\ub2e4\uc2a4\uc5d0\uc11c \ub370\uc774\ud130\ud504\ub808\uc784\uc740 \ud14c\uc774\ube14 \ud615\uc2dd\uc758 \ub370\uc774\ud130\uc14b\uc785\ub2c8\ub2e4. DBMS\uc758 Table\ub4e4 \uac04\uc5d0\ub3c4 Join\uc744 \ub9fa\uc744 \uc218 \uc788\ub4ef\uc774, \ub9c8\ucc2c\uac00\uc9c0\ub85c \ud310\ub2e4\uc2a4\uc758 \ub370\uc774\ud130\ud504\ub808\uc784\ub4e4 \uac04\uc5d0\ub3c4 Join\uc744 \ub9fa\uc744 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubb3c\ub860 Join\uc744 \ub9fa\uc744 \uacf5\ud1b5 \ud544\ub4dc\uac00 \uc874\uc7ac\ud55c\ub2e4\uba74 \ub9d0\uc785\ub2c8\ub2e4.<\/p>\n
Join\uc5d0\ub294 \ubaa8\ub450 4\uac00\uc9c0 \ubc29\uc2dd\uc774 \uc874\uc7ac\ud569\ub2c8\ub2e4. \uc989, \ub450 \ub370\uc774\ud130\uc14b \uac04\uc758 \uc911\ubcf5\ub41c \uc694\uc18c\ub9cc\uc744 Join\ud558\ub294 Inner Join\uacfc \ub450 \ub370\uc774\ud130\uc14b\uc5d0 \ub300\ud55c \ubaa8\ub4e0 \ub370\uc774\ud130\ub97c Join\ud558\ub294 Outter Join, \uadf8\ub9ac\uace0 \uc67c\ucabd \ub370\uc774\ud130\uc14b\uc744 \uae30\uc900\uc73c\ub85c \ud558\ub294 Left Join\uacfc \uc624\ub978\ucabd \ub370\uc774\ud130\uc14b\uc744 \uae30\uc900\uc73c\ub85c \ud558\ub294 Right Join\uc785\ub2c8\ub2e4. \ubcf4\ub2e4 \uba85\ud655\ud55c Join\uc758 \ud30c\uc545\uc740 \uc544\ub798\uc758 \ucf54\ub4dc \uc608\uc81c\ub97c \ud1b5\ud574 \ud30c\uc545\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
\uba3c\uc800 Join \ud558\uace0\uc790 \ud558\ub294 \ub370\uc774\ud130\uc14b\uc73c\ub85c, \ud310\ub2e4\uc2a4\uc758 \ub370\uc774\ud130\ud504\ub808\uc784\uc744 \uc544\ub798 \ucf54\ub4dc\ucc98\ub7fc \uc815\uc758\ud569\ub2c8\ub2e4.<\/p>\n
\r\nimport pandas as pd\r\n\r\ndata_A = {'key': [1,2,3], 'name': ['Jane', 'John', 'Peter']}\r\ndataframe_A = pd.DataFrame(data_A, columns = ['key', 'name'])\r\n\r\ndata_B = {'key': [2,3,4], 'age': [18, 15, 20]}\r\ndataframe_B = pd.DataFrame(data_B, columns = ['key', 'age'])\r\n\r\nprint(dataframe_A)\r\nprint(dataframe_B)\r\n<\/pre>\n\uacb0\uacfc\ub294 \uc544\ub798\uc640 \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\n key name\r\n0 1 Jane\r\n1 2 John\r\n2 3 Peter\r\n key age\r\n0 2 18\r\n1 3 15\r\n2 4 20<\/pre>\n\ub450 \ub370\uc774\ud130\ud504\ub808\uc784 \uac04\uc5d0\ub294 key\ub77c\ub294 \uacf5\ud1b5 \ud544\ub4dc\uac00 \uc874\uc7ac\ud558\ub294 \uac83\uc744 \ubcfc \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774\ub97c \ud1a0\ub300\ub85c \uba3c\uc800 Inner Join\uc5d0 \ub300\ud55c \ucf54\ub4dc\uc785\ub2c8\ub2e4.<\/p>\n
\r\ndf_INNER_JOIN = pd.merge(dataframe_A, dataframe_B, left_on='key', right_on='key', how='inner')\r\nprint(df_INNER_JOIN)\r\n<\/pre>\n\uc704\uc758 \ucf54\ub4dc\uc758 \uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\n key name age\r\n0 2 John 18\r\n1 3 Peter 15\r\n<\/pre>\n\ub2e4\uc74c\uc740 Outer Join\uc5d0 \ub300\ud55c \ucf54\ub4dc\uc785\ub2c8\ub2e4.<\/p>\n
\r\ndf_OUTER_JOIN = pd.merge(dataframe_A, dataframe_B, left_on='key', right_on='key', how='outer')\r\nprint(df_OUTER_JOIN)\r\n<\/pre>\n\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\n key name age\r\n0 1 Jane NaN\r\n1 2 John 18.0\r\n2 3 Peter 15.0\r\n3 4 NaN 20.0\r\n<\/pre>\n\ub2e4\uc74c\uc740 Left Join\uc5d0 \ub300\ud55c \ucf54\ub4dc\uc785\ub2c8\ub2e4.<\/p>\n
\r\ndf_LEFT_JOIN = pd.merge(dataframe_A, dataframe_B, left_on='key', right_on='key', how='left')\r\nprint(df_LEFT_JOIN)\r\n<\/pre>\n\uacb0\uacfc\ub294 \ub2e4\uc74c\uacfc \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\n key name age\r\n0 1 Jane NaN\r\n1 2 John 18.0\r\n2 3 Peter 15.0\r\n<\/pre>\n\ub2e4\uc74c\uc740 Right Join\uc5d0 \ub300\ud55c \ucf54\ub4dc\uc785\ub2c8\ub2e4.<\/p>\n
\r\ndf_RIGHT_JOIN = pd.merge(dataframe_A, dataframe_B, left_on='key', right_on='key', how='right')\r\nprint(df_RIGHT_JOIN)\r\n<\/pre>\n\ub2e4\uc74c\uc740 \uc2e4\ud589 \uacb0\uacfc\uc785\ub2c8\ub2e4.<\/p>\n
\r\n key name age\r\n0 2 John 18\r\n1 3 Peter 15\r\n2 4 NaN 20\r\n<\/pre>\n\ubaa8\ub4e0 Join\uc740 pd.merge \ud568\uc218\ub97c \ud1b5\ud574 \uc774\ub8e8\uc5b4\uc9c0\ub294\ub370\uc694. \uc704\uc758 \uc608\uc81c \ucf54\ub4dc\ub97c \ubcf4\uba74 \ub450 \ub370\uc774\ud130\ud504\ub808\uc784\uc758 Join \ud544\ub4dc\uac00 \ubaa8\ub450 ‘key’\ub77c\ub294 \uac83\uc744 \uc54c \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774\ucc98\ub7fc Join \ud544\ub4dc\uc758 \uc774\ub984\uc774 \ub3d9\uc77c\ud560 \uacbd\uc6b0 pd.merge\uc758 left_on\uacfc right_on \uc778\uc790 \ub300\uc2e0 on \uc778\uc790 \ud558\ub098\ub85c \ub300\uccb4\uac00 \uac00\ub2a5\ud569\ub2c8\ub2e4. \uc608\ub97c\ub4e4\uc5b4, Inner Join\uc758 \uacbd\uc6b0\ub294 \uc544\ub798\uc640 \uac19\uc2b5\ub2c8\ub2e4.<\/p>\n
\r\ndf_INNER_JOIN = pd.merge(dataframe_A, dataframe_B, on='key')\r\n<\/pre>\npd.merge \ud568\uc218\uc758 \uc778\uc790\uc911 how\ub3c4 \uc0dd\ub7b5\ub418\uc5c8\ub294\ub370, \uc774\ub294 Inner Join\uc774 pd.merge\uc758 \uc778\uc790 how\uc758 \uae30\ubcf8\uac12\uc774\uae30 \ub54c\ubb38\uc785\ub2c8\ub2e4.<\/p>\n","protected":false},"excerpt":{"rendered":"
\ud310\ub2e4\uc2a4\uc5d0\uc11c \ub370\uc774\ud130\ud504\ub808\uc784\uc740 \ud14c\uc774\ube14 \ud615\uc2dd\uc758 \ub370\uc774\ud130\uc14b\uc785\ub2c8\ub2e4. DBMS\uc758 Table\ub4e4 \uac04\uc5d0\ub3c4 Join\uc744 \ub9fa\uc744 \uc218 \uc788\ub4ef\uc774, \ub9c8\ucc2c\uac00\uc9c0\ub85c \ud310\ub2e4\uc2a4\uc758 \ub370\uc774\ud130\ud504\ub808\uc784\ub4e4 \uac04\uc5d0\ub3c4 Join\uc744 \ub9fa\uc744 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \ubb3c\ub860 Join\uc744 \ub9fa\uc744 \uacf5\ud1b5 \ud544\ub4dc\uac00 \uc874\uc7ac\ud55c\ub2e4\uba74 \ub9d0\uc785\ub2c8\ub2e4. Join\uc5d0\ub294 \ubaa8\ub450 4\uac00\uc9c0 \ubc29\uc2dd\uc774 \uc874\uc7ac\ud569\ub2c8\ub2e4. \uc989, \ub450 \ub370\uc774\ud130\uc14b \uac04\uc758 \uc911\ubcf5\ub41c \uc694\uc18c\ub9cc\uc744 Join\ud558\ub294 Inner Join\uacfc \ub450 \ub370\uc774\ud130\uc14b\uc5d0 \ub300\ud55c \ubaa8\ub4e0 \ub370\uc774\ud130\ub97c Join\ud558\ub294 Outter Join, \uadf8\ub9ac\uace0 \uc67c\ucabd \ub370\uc774\ud130\uc14b\uc744 \uae30\uc900\uc73c\ub85c \ud558\ub294 Left … <\/p>\n