{"id":7490,"date":"2024-09-29T18:42:35","date_gmt":"2024-09-29T18:42:35","guid":{"rendered":"https:\/\/pohang.eduwp.kr\/?p=7490"},"modified":"2026-04-20T04:31:03","modified_gmt":"2026-04-20T04:31:03","slug":"%ed%85%8c%ec%9d%b4%eb%b8%94-%ec%83%9d%ec%84%b1-%ec%88%98%ec%a0%95-%ec%82%ad%ec%a0%9c-cte-%ec%97%b0%ec%8a%b5","status":"publish","type":"post","link":"https:\/\/pohang.eduwp.kr\/?p=7490","title":{"rendered":"9\uc8fc\ucc28-1 \ud14c\uc774\ube14 \uc0dd\uc131, \uc218\uc815, \uc0ad\uc81c , cte \uc5f0\uc2b5, Join \uc5f0\uc2b51"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_81 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"\ubaa9\ucc28 \ud1a0\uae00\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#%ED%85%8C%EC%8A%A4%ED%8A%B8_%ED%85%8C%EC%9D%B4%EB%B8%94_5%EA%B0%9C_%EC%97%B0%EC%8A%B5%ED%95%98%EA%B8%B0\" >\ud14c\uc2a4\ud2b8 \ud14c\uc774\ube14 5\uac1c \uc5f0\uc2b5\ud558\uae30<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#%EC%82%AD%EC%A0%9C%EC%9D%98_3%EA%B0%80%EC%A7%80_%ED%91%9C%ED%98%84\" >\uc0ad\uc81c\uc758 3\uac00\uc9c0 \ud45c\ud604<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-1'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#join_%EB%AA%85%EB%A0%B9%EC%96%B4\" >join \uba85\ub839\uc5b4<\/a><ul class='ez-toc-list-level-2' ><li class='ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#%EC%97%B0%EC%8A%B5\" >\uc5f0\uc2b5<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#%EC%8B%A4%EC%8A%B5%EB%AA%85%EB%A0%B9%EC%96%B4\" >\uc2e4\uc2b5\uba85\ub839\uc5b4<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#%ED%85%8C%EC%9D%B4%EB%B8%94_%EC%97%B0%EA%B2%B0_%EA%B7%B8%EB%A6%BC\" >\ud14c\uc774\ube14 \uc5f0\uacb0 \uadf8\ub9bc<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#1%EB%8C%80_%EB%8B%A4%EC%9D%98_%EA%B4%80%EA%B3%84%EB%A5%BC_%EB%B0%98%EB%93%9C%EC%8B%9C_%EC%9D%B5%ED%98%80%EC%95%BC_%ED%95%9C%EB%8B%A4\" >1\ub300 \ub2e4\uc758 \uad00\uacc4\ub97c \ubc18\ub4dc\uc2dc \uc775\ud600\uc57c \ud55c\ub2e4.<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#PK_FK_%EA%B0%9C%EB%85%90%EC%9D%84_%EB%B0%98%EB%93%9C%EC%8B%9C_%EC%9D%B5%ED%9E%8C%EB%8B%A4\" >PK , FK \uac1c\ub150\uc744 \ubc18\ub4dc\uc2dc \uc775\ud78c\ub2e4.<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#foreign_key%EC%9D%98_%EC%97%AD%ED%99%9C%EC%9D%B4_%EB%AC%B4%EC%97%87%EC%9D%B8%EC%A7%80_%ED%99%95%EC%9D%B8\" >foreign key\uc758 \uc5ed\ud65c\uc774 \ubb34\uc5c7\uc778\uc9c0 \ud655\uc778<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/pohang.eduwp.kr\/?p=7490\/#%ED%9A%8C%EC%9B%90%EC%A0%95%EB%B3%B4_%EC%82%AD%EC%A0%9C%EC%8B%9C_%EC%97%90%EB%9F%AC%EB%82%98%EB%8A%94_%EA%B2%BD%EC%9A%B0\" >\ud68c\uc6d0\uc815\ubcf4 \uc0ad\uc81c\uc2dc \uc5d0\ub7ec\ub098\ub294 \uacbd\uc6b0<\/a><\/li><\/ul><\/li><\/ul><\/nav><\/div>\n<h1><span class=\"ez-toc-section\" id=\"%ED%85%8C%EC%8A%A4%ED%8A%B8_%ED%85%8C%EC%9D%B4%EB%B8%94_5%EA%B0%9C_%EC%97%B0%EC%8A%B5%ED%95%98%EA%B8%B0\"><\/span>\ud14c\uc2a4\ud2b8 \ud14c\uc774\ube14 5\uac1c \uc5f0\uc2b5\ud558\uae30<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">use sqldb;\r\n\r\ncreate table testTBL1 \r\n(\r\n    id int,\r\n    userName char(3),\r\n    age int\r\n);\r\n\r\n\r\ncreate table testTBL2 \r\n(\r\n    id int AUTO_INCREMENT PRIMARY KEY,\r\n    userName char(3),\r\n    age int\r\n);\r\n\r\ncreate table testTBL3 \r\n(\r\n    id int AUTO_INCREMENT PRIMARY KEY,\r\n    userName char(3),\r\n    age int\r\n);\r\n\r\nALTER TABLE testTBL3 AUTO_INCREMENT = 1000;\r\nset @@auto_increment_increment=3;\r\n\r\n\r\ninsert into testTBL3 VALUES (null, '\uc9c0\ubbfc', 25);\r\ninsert into testTBL3 VALUES (null, '\uc218\uc601', 22);\r\ninsert into testTBL3 VALUES (null, '\uc9c0\ubbfc', 25),(null, '\ubbfc\uacbd', 25),(null, '\uc740\ud654', 27);\r\n\r\ninsert into testTBL1 VALUE ( 1, '\ud64d\uae38\ub3d9', 25);\r\ninsert into testTBL1(id, userName) VALUE ( 2, '\uae40\uc131\uc2e4');\r\n\r\n\r\nSELECT * from testTBL3;\r\n\r\nCREATE table testTBL4 (\r\n    id int,\r\n    Fname varchar(50),\r\n    Lname varchar(50)\r\n);\r\n\r\ninsert into testTBL4 SELECT emp_no, first_name, last_name from employees.employees;\r\n\r\nSELECT * from testTBL4;\r\nSELECT * from employees.employees;\r\n\r\n\r\nCREATE TABLE testTBL5 (SELECT emp_no, first_name, last_name from employees.employees);\r\n\r\nselect * from testTBL5;<\/pre>\n<p>&nbsp;<\/p>\n<p>\ub0b4\uc6a9\uc744 \uc218\uc815\ud560 \ub54c \uc0ac\uc6a9, \ud544\ub4dc\uac00 \ubaa8\ub450 \ud55c\uaebc\ubc88\uc5d0 \uc218\uc815\ub420 \uc218 \uc788\uc73c\ub2c8 \ub9e4\uc6b0 \uc870\uc2ec<\/p>\n<p>where \uc870\uac74\uc808\uc744 \ubc18\ub4dc\uc2dc \ud568\uaed8 \uc0ac\uc6a9\ud55c\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">UPDATE testTBL4 set Lname = '\uc5c6\uc74c' where Fname = 'Kyoichi';<\/pre>\n<p>&nbsp;<\/p>\n<p>\uc804\uccb4 \uac00\uaca9\ud45c\uc758 \uac00\uaca9\uc744 2\ubc30\ub85c \uc62c\ub9b4\ub54c where \uc5c6\uc774 \ud544\ub4dc\uc5d0 \ud55c\uaebc\ubc88\uc5d0 \uc801\uc6a9 \ud55c\ub2e4.<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">UPDATE buytbl set price = price \/ 2;\r\n\r\nSELECT * from buytbl;<\/pre>\n<p>&nbsp;<\/p>\n<p>&#8212; \uc0ad\uc81c\ud560\ub54c \uc774\ub984\uc744 \uac80\uc0c9\ud558\uace0 limit\ub97c \uac78\uc5b4\uc11c \uc22b\uc790\ub9cc\ud07c\ub9cc \uc0ad\uc81c\ud560 \uc218 \uc788\ub2e4.<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">DELETE from testTBL4 WHERE Fname = 'Aamer';\r\nDELETE from testTBL4 WHERE Fname = 'Aamer' LIMIT 5;<\/pre>\n<p>&nbsp;<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%EC%82%AD%EC%A0%9C%EC%9D%98_3%EA%B0%80%EC%A7%80_%ED%91%9C%ED%98%84\"><\/span>\uc0ad\uc81c\uc758 3\uac00\uc9c0 \ud45c\ud604<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">CREATE TABLE bigTBL1 (SELECT * FROM employees.employees);\r\nCREATE TABLE bigTBL2 (SELECT * FROM employees.employees);\r\nCREATE TABLE bigTBL3 (SELECT * FROM employees.employees);\r\n\r\nDELETE from bigTBL1;\r\nSELECT * from bigTBL1;\r\n\r\nDROP table bigTBL2;\r\nSELECT * from bigTBL2;\r\n\r\nTRUNCATE table bigTBL3;\r\nSELECT * from bigTBL3;<\/pre>\n<p>delete \ub294 \ud55c\uc904\uc529 \uc2e4\ud589<\/p>\n<p>drop\uc640 truncate\ub294 \ud55c\ubc29\uc5d0 \uc2e4\ud589<\/p>\n<p>\uc2dc\uac04\uc758 \ucc28\uc774\uac00 \ub09c\ub2e4.<\/p>\n<hr \/>\n<p>\uc0c1\ud669\uc2e4\uc2b5<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">use employees;\r\n\r\nSELECT * from employees;\r\n\r\n-- abdDB\ub97c \uac00\ub3d9\uc2dc\ud0a8\ub2e4.\r\nuse abcdb;\r\n\r\n-- testtbl4 \ud14c\uc774\ube14 \uc6d0\ubcf8\uacfc \ube44\uad50\ud574\uc11c \ud0c0\uc785\uc744 \ube44\uc2b7\ud558\uac8c \ub9de\ucda5\ub2c8\ub2e4. \r\ncreate\tTABLE testtbl4 (\r\n    emp_no int,\r\n    first_name VARCHAR(30),\r\n    last_name VARCHAR(30)\r\n);\r\n\r\n-- emp_no, first_name, last_name \ud14c\uc774\ube14\uac12\uc744 \uc804\ubd80\ub2e4 \ub123\uc5b4\uc8fc\uc138\uc694. testtbl4\uc5d0 \ub123\uc5b4\uc8fc\uc138\uc694 (\ubcf5\uc0ac\ud574\uc8fc\uc138\uc694)\r\ninsert into testtbl4 select emp_no, first_name, last_name from employees.employees;<\/pre>\n<p>&nbsp;<\/p>\n<hr \/>\n<h1><span class=\"ez-toc-section\" id=\"join_%EB%AA%85%EB%A0%B9%EC%96%B4\"><\/span>join \uba85\ub839\uc5b4<span class=\"ez-toc-section-end\"><\/span><\/h1>\n<p>join\uba85\ub839\uc744 \uc0ac\uc6a9\ud558\ub294 \uc774\uc720 : \ub370\uc774\ud130\uc758 \ucd5c\uc801\uc758 \uc0ac\uc774\uc988\uc640 \ubd88\ud544\uc694\ud55c \ub370\uc774\ud130 \uc911\ubcf5\uc744 \ub9c9\uae30 \uc704\ud568, \ub370\uc774\ud130\uc758 \ubb34\uacb0\uc131\uc744 \uc704\ud574\uc11c \uc5ec\ub7ec \uac1c\uc758 \ud14c\uc774\ube14\uc744 \ubd84\ub9ac\ud558\uc5ec \uc800\uc7a5\ud55c\ub2e4.<\/p>\n<p>\ubd84\ub9ac\ub41c \ub370\uc774\ud130\ub97c \uc870\ud569\ud574\uc11c \uc0ac\uc6a9\ud560 \ub54c join \uba85\ub839\uc5b4\ub97c \uc0ac\uc6a9\ud558\uba70 join \uba85\ub839\uc5b4\ub294 \ub108\ubb34 \ub9ce\uc774 \uc0ac\uc6a9\ud558\uba74 \uc2dc\uc2a4\ud15c\uc5d0 \ubd80\ud558\uac00 \uc62c \uc218 \uc788\ub2e4.<\/p>\n<p>join \uba85\ub839\uc5b4\ub294 \uac1c\ubc1c\uc790\ubcf4\ub2e4 \ub370\uc774\ud130\ub97c \ubd84\uc11d\ud558\ub294 \uc785\uc7a5\uc5d0\uc11c \ub9ce\uc774 \uc0ac\uc6a9\ud558\ub294 \uba85\ub839\uc5b4\uc774\ub2e4.<\/p>\n<p>join \uc740 inner join\uc774\ub77c\uace0 \ub9d0\ud558\uba70 \ub450 \ud14c\uc774\ube14\uc5d0 \ud574\ub2f9 \ud544\ub4dc\uac12\uc774 \ub9e4\uce6d\ub418\ub294 \ub808\ucf54\ub4dc\ub9cc \uac00\uc838\uc628\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%EC%97%B0%EC%8A%B5\"><\/span>\uc5f0\uc2b5<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ul>\n<li>usertbl \uacfc buytbl \ud14c\uc774\ube14\uac04\uc758 2\uac1c \ub370\uc774\ud130\ub97c \uc870\ud569\ud574\uc11c \ud558\ub098\uc758 \ud569\uccd0\uc9c4 \ud14c\uc774\ube14\uc744 \uc0dd\uc131\ud574\uc11c \ud654\uba74\uc5d0 \ubcf4\uc5ec\uc8fc\ub294 \ubc29\ubc95<\/li>\n<li>usertbl\uc5d0\uc11c ID\ub294 \uc720\ub2c8\ud06c\ud55c \uac12 (primary key) \uc774\uba70 \uc544\uc774\ub514\uac00 KBS\uc778 \uc0ac\ub78c\uc758 \uc544\uc774\ub514\ub97c \ub2e4\ub978 \uc0ac\ub78c\uc774 \uc0ac\uc6a9\ud560 \uc218 \uc5c6\ub2e4.<\/li>\n<li>1\ub300\ub2e4 \uad00\uacc4\uc774\ub2e4. \uc989,\u00a0 usertbl\uc5d0\uc11c \ub2e4\ub978 \ucd94\uac00\ub41c \ud14c\uc774\ube14\uc744 \uc5f0\uacb0\ud574\uc11c \uc0ac\uc6a9\ud55c\ub2e4.<\/li>\n<li>\ud68c\uc6d0\ud14c\uc774\ube14\uc758 \uc544\uc774\ub514\ub294 Primary Key \ub85c \uc9c0\uc815\ud558\uace0\u00a0 \uad6c\ub9e4\ud14c\uc774\ube14\uc758 \uc544\uc774\ub514\ub294 Primary Key\uc640 \uc5f0\uacb0\ub41c Foreign Key\ub85c \uc9c0\uc815\ud55c\ub2e4.<\/li>\n<\/ul>\n<hr \/>\n<p>&nbsp;<\/p>\n<h2><span class=\"ez-toc-section\" id=\"%EC%8B%A4%EC%8A%B5%EB%AA%85%EB%A0%B9%EC%96%B4\"><\/span>\uc2e4\uc2b5\uba85\ub839\uc5b4<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>SELECT &lt;\uc5f4 \ubaa9\ub85d&gt;<\/p>\n<p>FROM &lt;\uccab \ubc88\uc9f8 \ud14c\uc774\ube14&gt; -&gt; buytbl<\/p>\n<p>INNER JOIN &lt;\ub450 \ubc88\uc9f8 \ud14c\uc774\ube14&gt; usertbl<\/p>\n<p>ON &lt;\uc870\uc778\ub420 \uc870\uac74&gt;\u00a0 buytbl.userID = usertbl.userID<\/p>\n[WHERE \uac80\uc0c9\uc870\uac74] buytbl.userID \uc911 &#8216;kbs&#8217; \uc778 \uc0ac\ub78c\ub9cc \ucd9c\ub825\ud558\uae30<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"%ED%85%8C%EC%9D%B4%EB%B8%94_%EC%97%B0%EA%B2%B0_%EA%B7%B8%EB%A6%BC\"><\/span>\ud14c\uc774\ube14 \uc5f0\uacb0 \uadf8\ub9bc<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-7540\" src=\"https:\/\/pohang.eduwp.kr\/wp-content\/uploads\/2024\/09\/20241023_231718.jpg\" alt=\"\" width=\"1023\" height=\"686\" srcset=\"https:\/\/pohang.eduwp.kr\/wp-content\/uploads\/2024\/09\/20241023_231718.jpg 1023w, https:\/\/pohang.eduwp.kr\/wp-content\/uploads\/2024\/09\/20241023_231718-300x201.jpg 300w, https:\/\/pohang.eduwp.kr\/wp-content\/uploads\/2024\/09\/20241023_231718-768x515.jpg 768w, https:\/\/pohang.eduwp.kr\/wp-content\/uploads\/2024\/09\/20241023_231718-600x403.jpg 600w, https:\/\/pohang.eduwp.kr\/wp-content\/uploads\/2024\/09\/20241023_231718-900x604.jpg 900w, https:\/\/pohang.eduwp.kr\/wp-content\/uploads\/2024\/09\/20241023_231718-400x269.jpg 400w\" sizes=\"auto, (max-width: 1023px) 100vw, 1023px\" \/><\/p>\n<p>userID\uac12\uc758 \uc815\ud655\ud55c \uc704\uce58\ub97c \uc120\uc5b8\ud558\uba74 \uc5d0\ub7ec\uac00 \ubc1c\uc0dd\ud558\uc9c0 \uc54a\ub294\ub2e4.<\/p>\n<hr \/>\n<h2><\/h2>\n<h2><span class=\"ez-toc-section\" id=\"1%EB%8C%80_%EB%8B%A4%EC%9D%98_%EA%B4%80%EA%B3%84%EB%A5%BC_%EB%B0%98%EB%93%9C%EC%8B%9C_%EC%9D%B5%ED%98%80%EC%95%BC_%ED%95%9C%EB%8B%A4\"><\/span>1\ub300 \ub2e4\uc758 \uad00\uacc4\ub97c \ubc18\ub4dc\uc2dc \uc775\ud600\uc57c \ud55c\ub2e4.<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h2><span class=\"ez-toc-section\" id=\"PK_FK_%EA%B0%9C%EB%85%90%EC%9D%84_%EB%B0%98%EB%93%9C%EC%8B%9C_%EC%9D%B5%ED%9E%8C%EB%8B%A4\"><\/span>PK , FK \uac1c\ub150\uc744 \ubc18\ub4dc\uc2dc \uc775\ud78c\ub2e4.<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<h2><span class=\"ez-toc-section\" id=\"foreign_key%EC%9D%98_%EC%97%AD%ED%99%9C%EC%9D%B4_%EB%AC%B4%EC%97%87%EC%9D%B8%EC%A7%80_%ED%99%95%EC%9D%B8\"><\/span>foreign key\uc758 \uc5ed\ud65c\uc774 \ubb34\uc5c7\uc778\uc9c0 \ud655\uc778<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\ud68c\uc6d0\ub370\uc774\ud130\uac00 \uc5c6\ub294\ub370 \ud68c\uc6d0\uad6c\ub9e4 \uc815\ubcf4 \ub370\uc774\ud130\ub97c \ub123\uc73c\uba74 fk\uac00 \ub9c9\uc544\uc8fc\ub294 \uc5ed\ud65c\uc744 \ud55c\ub2e4. \ub370\uc774\ud130 \ubb34\uacb0\uc131\uc744 \uc704\ud574\uc11c \uc874\uc7ac\ud558\uace0 \ud14c\uc774\ube14\uac04\uc774 \uc5f0\uacb0\uc744 \ubcf4\uc7a5<\/p>\n<hr \/>\n<h2><span class=\"ez-toc-section\" id=\"%ED%9A%8C%EC%9B%90%EC%A0%95%EB%B3%B4_%EC%82%AD%EC%A0%9C%EC%8B%9C_%EC%97%90%EB%9F%AC%EB%82%98%EB%8A%94_%EA%B2%BD%EC%9A%B0\"><\/span>\ud68c\uc6d0\uc815\ubcf4 \uc0ad\uc81c\uc2dc \uc5d0\ub7ec\ub098\ub294 \uacbd\uc6b0<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>\ubc18\ub300\ub85c \ud68c\uc6d0 \uc0ad\uc81c \uba85\ub839\uc5b4\ub97c \ud560\ub54c\ub3c4 \ubc14\ub85c \uc0ad\uc81c\ub294 \uc548\ub418\uace0 buytbl\uc5d0 \ub370\uc774\ud130\ub97c \uba3c\uc800 \uc0ad\uc81c\ud558\uace0 usertbl\uc5d0 \ud68c\uc6d0\uc815\ubcf4\ub97c \uc0ad\uc81c\ud560 \uc218 \uc788\ub2e4.<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">delete from buytbl where userid = 'stj';\r\n\r\ndelete from usertbl where userID = 'stj';<\/pre>\n<p>&nbsp;<\/p>\n<hr \/>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">USE sqldb;\r\nselect * from buytbl;\r\nselect * from usertbl;\r\nselect * from buytbl inner join usertbl on buytbl.userID = usertbl.userID where buytbl.userID ='KBS';\r\n\r\n<\/pre>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">USE sqldb; \r\nselect * from buytbl; select * from usertbl; \r\nselect * from buytbl inner join usertbl on buytbl.userID = usertbl.userID where order by ='num';<\/pre>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT \r\n    userID,\r\n    name,\r\n    prodName,\r\n    addr,\r\n    CONCAT(mobile1, mobile2) AS '\uc5f0\ub77d\ucc98'\r\nFROM\r\n    buytbl\r\n        INNER JOIN usertbl\r\n            ON buytbl.userID = usertbl.userID\r\nORDER BY num;<\/pre>\n<p>\uc624\ub958\uac00 \ubc1c\uc0dd\ud55c\ub2e4. \uc65c \ubc1c\uc0dd\ud558\ub294\uc9c0 \uc774\uc720 \uc54c\uc544\ubcf4\uae30<\/p>\n<p>userID\uac12\uc774 \uc5b4\ub290 \ud14c\uc774\ube14\uc758 userID\uc778\uc9c0 \ud655\uc778\ud560 \uc218 \uc5c6\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT \r\n    buytbl.userID,\r\n    name,\r\n    prodName,\r\n    addr,\r\n    CONCAT(mobile1, mobile2) AS '\uc5f0\ub77d\ucc98'\r\nFROM\r\n    buytbl\r\n        INNER JOIN usertbl\r\n            ON buytbl.userID = usertbl.userID\r\nORDER BY num;<\/pre>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT \r\n    buytbl.userID,\r\n    usertbl.name,\r\n    buytbl.prodName,\r\n    usertbl.addr,\r\n    CONCAT(usertbl.mobile1, usertbl.mobile2) AS '\uc5f0\ub77d\ucc98'\r\nFROM\r\n    buytbl\r\n        INNER JOIN usertbl\r\n            ON buytbl.userID = usertbl.userID\r\nORDER BY buytbl.num;<\/pre>\n<p>\ud14c\uc774\ube14\uba85\uc744 \ubaa8\ub450 \uc801\uc5b4\uc8fc\uba74 \uba85\ud655\ud558\uac8c \uc9c0\uc815\ud560 \uc218 \uc788\uc9c0\ub9cc \uae00\uc790\uac00 \uae38\uc5b4\uc9c0\ub294 \ubd88\ud3b8\ud568\uc774 \uc788\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT \r\n    B.userID,\r\n    U.name,\r\n    B.prodName,\r\n    U.addr,\r\n    CONCAT(U.mobile1, U.mobile2) AS '\uc5f0\ub77d\ucc98'\r\nFROM\r\n    buytbl B\r\n        INNER JOIN usertbl U\r\n            ON B.userID = U.userID\r\nORDER BY B.num;<\/pre>\n<p>\uc54c\ub77c\uc544\uc2a4 (\ubcc4\uce6d)\uc744 \uc0ac\uc6a9\uc790 \uc784\uc758\ub85c \uc785\ub825\ud574\uc11c \uc791\uc5c5\uc744 \uc9c4\ud589\ud558\uba74 \ub2e8\uc21c\ud654 \uc2dc\ud0ac \uc218 \uc788\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT \r\n    B.userID,\r\n    U.name,\r\n    B.prodName,\r\n    U.addr,\r\n    CONCAT(U.mobile1, U.mobile2) AS '\uc5f0\ub77d\ucc98'\r\nFROM\r\n    buytbl B\r\n        INNER JOIN usertbl U\r\n            ON B.userID = U.userID\r\n            where B.userID ='BBK'\r\nORDER BY B.num;<\/pre>\n<p>\ud2b9\uc815 \uc544\uc774\ub514\uc758 \uc81c\ud488 \uad6c\ub9e4\ubaa9\ub85d\uacfc \uc5f0\ub77d\ucc98, \uc8fc\uc18c<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT \r\n    U.userID,\r\n    U.name,\r\n    B.prodName,\r\n    U.addr,\r\n    CONCAT(U.mobile1, U.mobile2) AS '\uc5f0\ub77d\ucc98'\r\nFROM\r\n    usertbl U\r\n        INNER JOIN buytbl b\r\n            ON U.userID = B.userID\r\nORDER BY U.userid;<\/pre>\n<p>\uae30\uc900\uc774 \ub418\ub294 \ud14c\uc774\ube141\uacfc \ud14c\uc774\ube142\ub97c \ubc14\uafd4\uc11c\ub3c4 \ubb34\ubc29\ud558\ub2e4.\u00a0 \uae30\uc900 \uc774\ub984\uc744 \ubc14\uafb8\uba74 \uc870\uac74\uc2dd\ub3c4 \ubcc0\uacbd\ud574\uc11c Join\uc744 \uc9c4\ud589\ud558\uba74 \ub41c\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT DISTINCT\r\n    U.userID, U.name, U.addr\r\n    FROM usertbl U\r\n        INNER JOIN buytbl B\r\n            ON U.userID = B.userID\r\nORDER BY U.userid;<\/pre>\n<p>\uad6c\ub9e4\ub97c \ud55c\ubc88\uc774\ub77c\ub3c4 \uacbd\ud5d8\uc774 \uc788\ub294 \ud68c\uc6d0\uc758 \ubaa9\ub85d\uc744 \ubf51\uace0 \uc911\ubcf5\uc740 \ud55c\uba85\ub9cc \ucd9c\ub825\ud55c\ub2e4.<\/p>\n<p>distinct \ub294 \uc911\ubcf5\ub418\ub294 \uacb0\uacfc\uc911 \ub300\ud45c\ub9cc \ucd9c\ub825\ud55c\ub2e4. \uc544\uc774\ub514,\uc774\ub984,\uc8fc\uc18c\ub9cc \uc11c\ub85c \uc870\uc778\ud574\uc11c \ud55c\ubc88\uc774\ub77c\ub3c4 \uad6c\ub9e4\ud55c \uc0ac\ub78c\uc744 \ubf51\uc544\uc11c \uc911\ubcf5\uc81c\uac70\ud558\uace0 \ub300\ud45c\ub9cc \ucd9c\ub825\ud55c\ub2e4.<\/p>\n<p>&nbsp;<\/p>\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\">SELECT DISTINCT\r\n    U.userID, U.name, U.addr\r\n    FROM usertbl U\r\n        WHERE EXISTS ( SELECT * from buytbl B where U.userID = B.userID);\r\n<\/pre>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\ud14c\uc2a4\ud2b8 \ud14c\uc774\ube14 5\uac1c \uc5f0\uc2b5\ud558\uae30 use sqldb; create table testTBL1 ( id int, userName char(3), age int ); create table testTBL2 ( id int AUTO_INCREMENT PRIMARY KEY, userName char(3), age int&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[],"class_list":["post-7490","post","type-post","status-publish","format-standard","category-mysql"],"_links":{"self":[{"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=\/wp\/v2\/posts\/7490","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7490"}],"version-history":[{"count":5,"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=\/wp\/v2\/posts\/7490\/revisions"}],"predecessor-version":[{"id":7578,"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=\/wp\/v2\/posts\/7490\/revisions\/7578"}],"wp:attachment":[{"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7490"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7490"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pohang.eduwp.kr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7490"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}