{"id":20206,"date":"2018-03-15T11:14:00","date_gmt":"2018-03-15T02:14:00","guid":{"rendered":"http:\/\/w3devlabs.net\/wp\/?p=20206"},"modified":"2018-03-14T23:14:18","modified_gmt":"2018-03-14T14:14:18","slug":"mysql-%eb%ac%b8%ec%9e%90%ec%97%b4-%ec%9e%90%eb%a5%b4%ea%b8%b0-%ed%95%a8%ec%88%98","status":"publish","type":"post","link":"http:\/\/w3devlabs.net\/wp\/?p=20206","title":{"rendered":"MySQL \ubb38\uc790\uc5f4 \uc790\ub974\uae30 \ud568\uc218"},"content":{"rendered":"

MySQL \ubb38\uc790\uc5f4 \uc790\ub974\uae30 \ud568\uc218<\/font><\/span><\/p>\n



<\/p>\n

1. \uc67c\ucabd\uc5d0\uc11c \ubb38\uc790\uc5f4 \uc790\ub974\uae30<\/font><\/font><\/span><\/h2>\n


<\/span>left(\uceec\ub7fc\uba85 \ub610\ub294 \ubb38\uc790\uc5f4, \uc67c\ucabd\uc5d0\uc11c \uc798\ub77c\ub0bc \ubb38\uc790\uc5f4\uc758 \uae38\uc774)<\/font><\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT left(“w3devlabs.net”, 5)<\/span>
<\/span><\/font>\uacb0\uacfc : w3dev<\/font><\/span><\/p>\n

<\/span>
<\/span> <\/font><\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT left(“w3devlabs.net”, 8)<\/span>
<\/span><\/font>\uacb0\uacfc : w3devlab<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT left(“20180323”, 4)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : 2018<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT left(“20180323”, 6)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : 201803<\/font><\/span>
<\/span><\/span>

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

2. \uc911\uac04\uc5d0\uc11c \ubb38\uc790\uc5f4 \uc790\ub974\uae30<\/font><\/font><\/span><\/h2>\n


<\/span>substring(\uceec\ub7fc \ub610\ub294 \ubb38\uc790\uc5f4, \uc2dc\uc791\uc704\uce58, \uae38\uc774);<\/font><\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT substring(“w3devlabs.net”, 3, 5)<\/span>
<\/span><\/font>\uacb0\uacfc : devla<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT substring(“w3devlabs.net”, 1, 5)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : w3dev<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT substring(“20180323”, 1, 4)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : 2018<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT substring(“20180323”, 1, 6)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : 201803<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT substring(“20180323”, 5, 2)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : 03<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\ucc38\uace0 : substr \ud568\uc218\ub294 \ubb38\uc790\uc5f4\uc758 \uc77c\ubd80\ub97c \ucd94\ucd9c\ud558\ub294 \ud568\uc218\ub85c substring \ud568\uc218\uc758 \ub3d9\uc758\uc5b4\uc785\ub2c8\ub2e4<\/font><\/span>
<\/span><\/font> <\/font><\/span>

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

3. \uc624\ub978\ucabd\uc5d0\uc11c \ubb38\uc790\uc5f4 \uc790\ub974\uae30<\/font><\/font><\/span>

<\/span><\/h2>\n

right(\uceec\ub7fc\uba85 \ub610\ub294 \ubb38\uc790\uc5f4, \uae38\uc774);<\/font><\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT right(“w3devlabs.net”, 7)<\/span>
<\/span><\/font>\uacb0\uacfc : lab.net<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT right(“w3devlabs.net”, 3)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : net<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT right(“20180323”, 4)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : 0323<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT right(“20180323”, 2)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : 23<\/font><\/span><\/p>\n

<\/span>
<\/span>

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

4. \uad6c\ubd84\uc790 (delimiter) delim\uac00 count \ub9cc\ud07c \ub098\uc624\uae30 \uc804\uc5d0 \uc2a4\ud2b8\ub9c1 str \uc5d0\uc11c \uc11c\ube0c \uc2a4\ud2b8\ub9c1\uc744 \ub9ac\ud134. <\/font><\/font><\/span>

<\/span><\/h2>\n

SUBSTRING_INDEX(str,delim,count)<\/font><\/span>
<\/span>
<\/span>\uad6c\ubd84\uc790 (delimiter) delim\uac00 count \ub9cc\ud07c \ub098\uc624\uae30 \uc804\uc5d0 \uc2a4\ud2b8\ub9c1 str \uc5d0\uc11c \uc11c\ube0c \uc2a4\ud2b8\ub9c1\uc744 \ub9ac\ud134\ud55c\ub2e4. <\/span>
<\/span>\ub9cc\uc77c count \uac00 \uc591\uc218 (positive)\ub77c\uba74, \ub9c8\uc9c0\ub9c9 \uad6c\ubd84\uc790\uc758 \uc67c\ucabd\uc5d0 \uc788\ub294 \ubaa8\ub4e0 \uac83\ub4e4\uc774 \ub9ac\ud134\ub41c\ub2e4.<\/span>
<\/span>(\uc67c\ucabd\ubd80\ud130 \uacc4\uc0b0\uc774 \ub428). \ub9cc\uc77c count \uac00 \uc74c\uc218\uc77c \uacbd\uc6b0\uc5d0\ub294, \ub9c8\uc9c0\ub9c9 \uad6c\ubd84\uc790\uc758 \uc624\ub978\ucabd\uc5d0 \uc788\ub294 \ubaa8\ub4e0 \uac83\ub4e4\uc774 \ub9ac\ud134\ub41c\ub2e4 (\uc624\ub978\ucabd\ubd80\ud130 \uacc4\uc0b0\ub428). <\/span>
<\/span>SUBSTRING_INDEX()\ub294 delim\uc5d0 \ub300\ud55c \uac80\uc0c9\uc744 \ud560 \ub54c \ubb38\uc790\uc758 \ud06c\uae30\ub97c \uad6c\ubd84\ud55c\ub2e4.<\/span>
<\/span> <\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT SUBSTRING_INDEX(‘www.w3devlabs.net’, ‘.’, 2);<\/span>
<\/span><\/font>\uacb0\uacfc : www.w3devlabs<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT SUBSTRING_INDEX(‘www.w3devlabs.net’, ‘.’, -2);<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : w3devlabs.net<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT SUBSTRING_INDEX(‘admin@w3devlabs.net’, ‘@’, -1)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : w3devlabs.net<\/font><\/span><\/p>\n

<\/span>
<\/span>
<\/span>\uc0ac\uc6a9\uc608 : SELECT SUBSTRING_INDEX(‘admin@w3devlabs.net’, ‘@’, 1)<\/font><\/span>
<\/span><\/font>\uacb0\uacfc : admin<\/font><\/span><\/p>\n

<\/span>
<\/span> <\/font><\/span>
<\/span><\/font>\uc774 \ud568\uc218\ub294 \ub2e4\uc911 \ubc14\uc774\ud2b8\ub97c \uc9c0\uc6d0\ud55c\ub2e4.<\/font><\/span><\/p>\n


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

MySQL \ubb38\uc790\uc5f4 \uc790\ub974\uae30 \ud568\uc218 1. \uc67c\ucabd\uc5d0\uc11c \ubb38\uc790\uc5f4 \uc790\ub974\uae30 left(\uceec\ub7fc\uba85 \ub610\ub294 \ubb38\uc790\uc5f4, \uc67c\ucabd\uc5d0\uc11c \uc798\ub77c\ub0bc \ubb38\uc790\uc5f4\uc758 \uae38\uc774)\uc0ac\uc6a9\uc608 : SELECT left(“w3devlabs.net”, 5)\uacb0\uacfc : w3dev \uc0ac\uc6a9\uc608 : SELECT left(“w3devlabs.net”, 8)\uacb0\uacfc : w3devlab \uc0ac\uc6a9\uc608 : SELECT left(“20180323”, 4)\uacb0\uacfc : 2018 \uc0ac\uc6a9\uc608 : SELECT left(“20180323”, 6)\uacb0\uacfc : 201803 2. \uc911\uac04\uc5d0\uc11c \ubb38\uc790\uc5f4 \uc790\ub974\uae30 substring(\uceec\ub7fc \ub610\ub294 \ubb38\uc790\uc5f4, \uc2dc\uc791\uc704\uce58, \uae38\uc774);\uc0ac\uc6a9\uc608 : SELECT substring(“w3devlabs.net”, 3, … <\/p>\n

\ub354 \ubcf4\uae30 “MySQL \ubb38\uc790\uc5f4 \uc790\ub974\uae30 \ud568\uc218”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[18240],"tags":[5417,24114],"class_list":["post-20206","post","type-post","status-publish","format-standard","hentry","category-mysql","tag-mysql","tag-24114","entry"],"_links":{"self":[{"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=\/wp\/v2\/posts\/20206","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=20206"}],"version-history":[{"count":1,"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=\/wp\/v2\/posts\/20206\/revisions"}],"predecessor-version":[{"id":20207,"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=\/wp\/v2\/posts\/20206\/revisions\/20207"}],"wp:attachment":[{"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=20206"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=20206"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/w3devlabs.net\/wp\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=20206"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}