{"id":716,"date":"2015-11-25T00:32:23","date_gmt":"2015-11-25T00:32:23","guid":{"rendered":"http:\/\/haisins.epac.to\/wordpress\/?p=716"},"modified":"2015-11-25T00:32:23","modified_gmt":"2015-11-25T00:32:23","slug":"%ec%a1%b0%ec%9d%b8%ec%9d%98-%ed%8a%9c%eb%8b%9d-%eb%b0%a9%eb%b2%95-2","status":"publish","type":"post","link":"http:\/\/haisins.synology.me\/wordpress\/?p=716","title":{"rendered":"\uc870\uc778\uc758 \ud29c\ub2dd \ubc29\ubc95 -2"},"content":{"rendered":"

Outer Join<\/span><\/p>\n

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\uc5b4\ub5a4 \uc9d1\ud569\uc744 \uae30\uc900\uc73c\ub85c \ud574\uc11c \uc870\uc778\ub418\ub294 \ub2e4\ub978 \uc9d1\ud569\uacfc\uc758 \uc5f0\uacb0\uc5d0 \uc2e4\ud328\ud588\ub354\ub77c\ub3c4 \uadf8 \uacb0\uacfc\ub97c \ucd94\ucd9c\ud558\ub294 \uc870\uc778<\/span><\/span><\/font><\/p>\n


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\ud2b9\uc9d5<\/span><\/span><\/font><\/p>\n

\uc870\uc778 \uc21c\uc11c\uac00 \ubbf8\ub9ac \uc815\ud574\uc9c0\ubbc0\ub85c \uc870\uc778\uc21c\uc11c\ub97c \uc774\uc6a9\ud55c \ud29c\ub2dd\uc774 \ubd88\uac00\ud568<\/span><\/span><\/font><\/p>\n

\uac00\ub2a5\ud55c Outer Join\uc740 \ud53c\ud558\ub3c4\ub85d \ud568<\/span><\/span><\/font><\/p>\n

Outer Join\uc744 \ub2f4\ub2f9\ud558\ub294 \ud14c\uc774\ube14\uc5d0 \ub300\ud55c \ubaa8\ub4e0 \uc870\uac74\uc5d0 (+)\uae30\ud638\uac00 \ubd99\uc5ec\uc57c \uc6d0\ud558\ub294 \uacb0\uacfc\ub97c \uc5bb\uc744 \uc218 \uc788\uc74c<\/span><\/span><\/font><\/p>\n

(+)\uae30\ud638\ub97c \uc774\uc6a9\ud558\uc5ec IN, OR\uc758 \uc5f0\uc0b0\uc790\ub97c \uc774\uc6a9\ud558\uc5ec \ube44\uad50\ud560 \uc218 \uc5c6\uc74c(Inline View\ub97c \uc774\uc6a9\ud558\uc5ec \ud574\uacb0)<\/span><\/span><\/font><\/p>\n<\/p>\n

(+)\uae30\ud638\ub97c \uc774\uc6a9\ud558\uc5ec subquery\uc640 \ube44\uad50\ud560 \uc218 \uc5c6\uc74c(OR IS NULL \uc870\uac74\uacfc \ube44\uad50\ud574\uc57c\ud568) <\/span><\/span><\/font><\/p>\n

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Semi Join<\/span><\/p>\n

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\uc870\uc778\uacfc \ub9e4\uc6b0 \uc720\uc0ac\ud55c \ub370\uc774\ud130 \uc5f0\uacb0 \ubc29\ubc95<\/span><\/span><\/font><\/p>\n

\uc11c\ube0c\ucffc\ub9ac\ub97c \uc0ac\uc6a9\ud588\uc744 \ub54c \uba54\uc778 \ucffc\ub9ac\uc640\uc758 \uc5f0\uacb0\ud558\ub294 \ucc98\ub9ac<\/span><\/span><\/font><\/p>\n<\/p>\n

Nested Loop \ud615, Sort Merge \ud615, Hash \ud615, Filter \ud615 \ub4f1<\/span><\/span><\/font><\/p>\n


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Anti Join<\/span><\/p>\n


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\n

\ubd80\uc815\ud615(NOT) \uc220\uc5b4\ub97c \uc0ac\uc6a9\ud558\ub294 \uc11c\ube0c\ucffc\ub9ac\uac00 \uc788\ub294 SELECT\ubb38<\/span><\/span><\/font><\/p>\n


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# \uc720\ud615\ubcc4 \uc870\uc778 \ud29c\ub2dd \uac00\uc774\ub4dc \uc694\uc57d #<\/b><\/span><\/p>\n


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– \uc870\uc778\uc21c\uc11c<\/b><\/span><\/font><\/p>\n


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\uc870\uc778 \uc218\ud589\uc758 \ud6a8\uc728\uc740 \uc870\uc778 \uac01 \ub300\uc0c1 \uc9d1\ud569\uc758 \ucc98\ub9ac \ubc94\uc704\uc640 \uc870\uc778\uc758 \uc21c\uc11c\uac00 \uc911\uc694\ud568<\/b><\/span><\/font><\/p>\n

\uc21c\uc11c\uac00 \uc801\uc808\ud558\uc9c0 \ubabb\ud560 \uacbd\uc6b0 \ucc98\ub9ac\ubc94\uc704 \uacfc\ub2e4\ub85c \uc561\uc138\uc2a4 \ub7c9\uc774 \uc99d\uac00\ud558\uc5ec \uc131\ub2a5 \uc800\ud558 \ubc1c\uc0dd<\/b><\/span><\/font><\/p>\n

\n


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<\ud29c\ub2dd \uac00\uc774\ub4dc><\/b><\/span><\/font><\/p>\n


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Nested Loop \uc870\uc778 \uacbd\uc6b0, \ucc98\ub9ac \ubc94\uc704\ub97c \ucd5c\uc18c\ud654 \ud560 \uc218 \uc788\ub3c4\ub85d Driving \ud14c\uc774\ube14 \uc120\uc815<\/p>\n

\uc870\uc778\uc758 \ucc98\ub9ac \ubc94\uc704 \ucd5c\uc18c\ud654\uac00 \uc911\uc694\ud558\ub098 \uc778\ub371\uc2a4 \uc2a4\uce94\uc758 \ubc29\ud574(\uceec\ub7fc \ub0b4\/\uc678\ubd80 \ubcc0\ud615 \ub4f1) \ub4f1\uc758 \uc774\uc720\ub85c \uc801\uc808\ud55c \uc778\ub371\uc2a4 \uc120\ud0dd\uc774 \uc5b4\ub824\uc6cc \uc9d0\uc73c\ub85c\uc368 \uc870\uc778 \uc21c\uc11c\uc5d0 \uc624\ub958 \ubc1c\uc0dd \uac00\ub2a5<\/p>\n

\ud1b5\uacc4\uc815\ubcf4\uac00 \uc815\ud655\ud558\uc9c0 \ubabb\ud560 \uacbd\uc6b0, \ucc98\ub9ac \ubc94\uc704\ub97c \ucd5c\uc18c\ud654\ud560 \uc218 \uc788\ub294 \ud14c\uc774\ube14 \uc120\uc815\uc5d0 \uc624\ub958 \ubc1c\uc0dd \uac00\ub2a5<\/p>\n

\ubd80\uc801\uc808\ud55c \ud78c\ud2b8(ordered) \uc0ac\uc6a9\uc2dc \uc870\uc778\uc758 \uc21c\uc11c\uc5d0 \uc624\ub958 \ubc1c\uc0dd \uac00\ub2a5<\/p>\n

\uc870\uc778 \ub300\uc0c1\uc774 \uacfc\ub2e4\ud558\uace0 \ubc29\ubc95\uc774 \ubcf5\uc7a1\ud560 \uacbd\uc6b0, \ud1b5\uacc4\uc815\ubcf4\uc640 \uad6c\ubb38\uc0c1\uc5d0 \uc774\uc0c1\uc774 \uc5c6\uc744 \uc9c0\ub77c\ub3c4 \uc870\uc778\uc758 \uc21c\uc11c\uc5d0 \uc624\ub958\uac00 \ubc1c\uc0dd \uac00\ub2a5<\/p>\n

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<\ud29c\ub2dd \ubc29\ubc95><\/b><\/p>\n


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<\/span>\ud1b5\uacc4\uc815\ubcf4 \uc0dd\uc131<\/span><\/span>\/<\/span>\uac31\uc2e0<\/span><\/p>\n

\uad6c\ubb38 \ub0b4 \uc870\uc778 \ud45c\ud604\uc758 \uba85\ub8cc\ud654<\/span><\/p>\n

\ubd80\uc801\uc808\ud55c \ud78c\ud2b8 \uc81c\uac70<\/span><\/span><\/p>\n

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\uc870\uc778 \uc21c\uc11c \uac15\uc81c\ud654 \ud78c\ud2b8 \uc801\uc6a9<\/span><\/span>(ORDERED)<\/span><\/span><\/span><\/p>\n


<\/span><\/span><\/p>\n

Index Range Scan<\/span><\/p>\n

(\uacb0\ud569\uc778\ub371\uc2a4)<\/span><\/p>\n


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<\/span><\/span><\/p>\n

\uacb0\ud569 \uc778\ub371\uc2a4\uc758 \uac00\uc7a5 \ud070 \ud2b9\uc9d5\uc740 \uc120\ub450 \uceec\ub7fc\uc774 (=,in)\uc73c\ub85c \ub4e4\uc5b4\uc624\uc9c0 \uc54a\uc544\uc11c \ubc94\uc704\uac00 \ub113\uc5b4\uc9c8 \uacbd\uc6b0\uc5d0 <\/font><\/p>\n

\ud6c4\ud589 \uceec\ub7fc\uc758 selectivity\uac00 \uc88b\ub2e4\uace0 \ud560\uc9c0\ub77c\ub3c4 \uc778\ub371\uc2a4\ub97c \uc561\uc138\uc2a4\ud558\ub294 \ubc94\uc704\ub97c \uc904\uc5ec\uc8fc\uc9c0 \ubabb\ud558\uace0, \ud14c\uc774\ube14\uc744 \uc561\uc138\uc2a4\ud558\ub294 \ubc94\uc704\ub9cc\uc744 \uc904\uc5ec \uc904 \uc218 \uc788\uc74c.<\/font><\/p>\n


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\uacb0\ud569 \uc778\ub371\uc2a4\uc758 \uccab \ubc88\uc9f8 \uce7c\ub7fc\uc774 \u2018=\u2018 \uc870\uac74\uc73c\ub85c \uc0ac\uc6a9\ub420 \uacbd\uc6b0 2\ubc88\uc9f8 \uc774\ud6c4\uc758 \uc778\ub371\uc2a4 \uce7c\ub7fc\uc774 \uc778\ub371\uc2a4\ub85c\uc11c\uc758 \uc5ed\ud560\uc744 \ud560 \uc218 \uc788\uc73c\ubbc0\ub85c <\/font><\/p>\n

\uc778\ub371\uc2a4\ub97c \uc561\uc138\uc2a4\ud558\ub294 \ubc94\uc704\ub97c \uc904\uc5ec\uc904 \uc218 \uc788\uc74c<\/font><\/p>\n


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<\/span><\/span><\/font><\/p>\n<\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Outer Join \uc5b4\ub5a4 \uc9d1\ud569\uc744 \uae30\uc900\uc73c\ub85c \ud574\uc11c \uc870\uc778\ub418\ub294 \ub2e4\ub978 \uc9d1\ud569\uacfc\uc758 \uc5f0\uacb0\uc5d0 \uc2e4\ud328\ud588\ub354\ub77c\ub3c4 \uadf8 \uacb0\uacfc\ub97c \ucd94\ucd9c\ud558\ub294 \uc870\uc778 \ud2b9\uc9d5 \uc870\uc778 \uc21c\uc11c\uac00 \ubbf8\ub9ac \uc815\ud574\uc9c0\ubbc0\ub85c \uc870\uc778\uc21c\uc11c\ub97c \uc774\uc6a9\ud55c \ud29c\ub2dd\uc774 \ubd88\uac00\ud568 \uac00\ub2a5\ud55c Outer Join\uc740 \ud53c\ud558\ub3c4\ub85d \ud568 Outer Join\uc744 \ub2f4\ub2f9\ud558\ub294 \ud14c\uc774\ube14\uc5d0 \ub300\ud55c \ubaa8\ub4e0 \uc870\uac74\uc5d0 (+)\uae30\ud638\uac00 \ubd99\uc5ec\uc57c \uc6d0\ud558\ub294 \uacb0\uacfc\ub97c \uc5bb\uc744 \uc218 \uc788\uc74c (+)\uae30\ud638\ub97c \uc774\uc6a9\ud558\uc5ec IN, OR\uc758 \uc5f0\uc0b0\uc790\ub97c \uc774\uc6a9\ud558\uc5ec \ube44\uad50\ud560 \uc218 \uc5c6\uc74c(Inline View\ub97c \uc774\uc6a9\ud558\uc5ec \ud574\uacb0) […]<\/p>\n","protected":false},"author":1,"featured_media":717,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"spay_email":""},"categories":[11],"tags":[401,288,118],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/haisins.synology.me\/wordpress\/wp-content\/uploads\/1\/cfile7.uf.22248C385654FFFA30235D.png?fit=601%2C177","amp_enabled":true,"_links":{"self":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/716"}],"collection":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=716"}],"version-history":[{"count":0,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/716\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=\/wp\/v2\/media\/717"}],"wp:attachment":[{"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=716"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=716"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/haisins.synology.me\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=716"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}