{"id":1119,"date":"2024-12-29T15:25:48","date_gmt":"2024-12-29T06:25:48","guid":{"rendered":"https:\/\/route-zero.com\/recruit\/route\/1119\/"},"modified":"2025-03-28T15:30:30","modified_gmt":"2025-03-28T06:30:30","slug":"1119","status":"publish","type":"route","link":"https:\/\/route-zero.com\/recruit\/route\/1119\/","title":{"rendered":"SQL JOIN\u306e\u57fa\u672c\u304b\u3089\u5b9f\u8df5\u307e\u3067\uff5cINNER\u30fbLEFT\u30fbRIGHT\u30fbOUTER JOIN\u306e\u9055\u3044\u3092\u308f\u304b\u308a\u3084\u3059\u304f\u89e3\u8aac"},"content":{"rendered":"<div>\n<h2>\u306f\u3058\u3081\u306b<\/h2>\n<p>\u300cSQL\u306eJOIN\u3063\u3066\u96e3\u3057\u305d\u3046\u300d\u300c\u5b9f\u969b\u306e\u4f7f\u3044\u65b9\u304c\u3088\u304f\u5206\u304b\u3089\u306a\u3044\u300d\u305d\u3046\u611f\u3058\u3066\u3044\u307e\u305b\u3093\u304b\uff1f<\/p>\n<p>\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u3092\u6271\u3046\u4e0a\u3067\u3001\u30c6\u30fc\u30d6\u30eb\u540c\u58eb\u3092\u7d50\u3073\u3064\u3051\u308bJOIN\u306f\u907f\u3051\u3066\u306f\u901a\u308c\u306a\u3044\u8d85\u91cd\u8981\u6a5f\u80fd\u3067\u3059\u3002\u3057\u304b\u3057\u3001\u7528\u8a9e\u3060\u3051\u3092\u4e26\u3079\u3089\u308c\u3066\u3082\u30d4\u30f3\u3068\u3053\u306a\u3044\u306e\u304c\u6b63\u76f4\u306a\u3068\u3053\u308d\u3067\u3059\u3088\u306d\u3002<\/p>\n<p>\u305d\u3053\u3067\u3053\u306e\u8a18\u4e8b\u3067\u306f\u3001JOIN\u3092\u300c\u5b9f\u969b\u306e\u8077\u5834\u306e\u540d\u7c3f\u300d\u3068\u300c\u90e8\u7f72\u4e00\u89a7\u8868\u300d\u306b\u4f8b\u3048\u306a\u304c\u3089\u3001\u5177\u4f53\u7684\u306a\u30a4\u30e1\u30fc\u30b8\u3092\u6301\u3066\u308b\u3088\u3046\u306b\u89e3\u8aac\u3057\u307e\u3059\u3002\u8a18\u4e8b\u3092\u8aad\u307f\u7d42\u308f\u308b\u9803\u306b\u306f\u3001inner join\u3001outer join\u3001left join\u3001right join\u306e\u9055\u3044\u3068\u4f7f\u3044\u65b9\u304c\u3059\u3063\u304d\u308a\u7406\u89e3\u3067\u304d\u307e\u3059\uff01<\/p>\n<hr>\n<h2>JOIN\u3068\u306f\uff1f\uff5c\u5b9f\u751f\u6d3b\u3067\u8a00\u3048\u3070\u540d\u7c3f\u306e\u7167\u3089\u3057\u5408\u308f\u305b<\/h2>\n<p>JOIN\u306f\u3001\u8907\u6570\u306e\u30c6\u30fc\u30d6\u30eb\u3092\u7d44\u307f\u5408\u308f\u305b\u3066\u3001\u6b32\u3057\u3044\u60c5\u5831\u3092\u4e00\u3064\u306b\u307e\u3068\u3081\u308b\u6280\u3067\u3059\u3002<\/p>\n<p>\u4f8b\u3048\u3070\u3001\u6b21\u306e\u3088\u3046\u306a2\u3064\u306e\u8868\uff08\u30c6\u30fc\u30d6\u30eb\uff09\u304c\u3042\u308b\u3068\u3057\u307e\u3059\uff1a<\/p>\n<ul>\n<li>\n<p><strong>\u793e\u54e1\u30ea\u30b9\u30c8<\/strong>\uff08\u793e\u54e1ID\u30fb\u540d\u524d\u30fb\u90e8\u7f72ID\uff09<\/p>\n<\/li>\n<li>\n<p><strong>\u90e8\u7f72\u30ea\u30b9\u30c8<\/strong>\uff08\u90e8\u7f72ID\u30fb\u90e8\u7f72\u540d\uff09<\/p>\n<\/li>\n<\/ul>\n<p>\u3053\u308c\u3063\u3066\u307e\u308b\u3067\u3001<\/p>\n<ul>\n<li>\n<p>\u300c\u793e\u54e1\u306e\u540d\u7c3f\u300d\u3068\u3001<\/p>\n<\/li>\n<li>\n<p>\u300c\u90e8\u7f72\u3054\u3068\u306e\u4e00\u89a7\u8868\u300d<\/p>\n<\/li>\n<\/ul>\n<p>\u304c\u5225\u3005\u306b\u5b58\u5728\u3057\u3066\u3044\u308b\u3088\u3046\u306a\u3082\u306e\u3067\u3059\u3002<\/p>\n<p>JOIN\u306f\u3001\u3053\u308c\u3089\u3092\u7167\u3089\u3057\u5408\u308f\u305b\u3066\u3001<\/p>\n<p>\u3068\u3044\u3046\u201c\u73fe\u5b9f\u3067\u3088\u304f\u3084\u308b\u4f5c\u696d\u201d\u3092\u30c7\u30fc\u30bf\u30d9\u30fc\u30b9\u4e0a\u3067\u81ea\u52d5\u5316\u3057\u3066\u304f\u308c\u308b\u6a5f\u80fd\u3067\u3059\u3002<\/p>\n<hr>\n<h2>4\u7a2e\u985e\u306eJOIN\u3092\u56f3\u3068\u4f8b\u3067\u7406\u89e3\u3059\u308b<\/h2>\n<h3>1. INNER JOIN\uff08\u5171\u901a\u3059\u308b\u30c7\u30fc\u30bf\u3060\u3051\u3092\u53d6\u5f97\uff09<\/h3>\n<p>\u793e\u54e1\u3068\u90e8\u7f72\u306e\u4e21\u65b9\u306b\u60c5\u5831\u304c\u63c3\u3063\u3066\u3044\u308b\u4eba\u3060\u3051\u3092\u8868\u793a\u3057\u307e\u3059\u3002<\/p>\n<pre><code>SELECT \u793e\u54e1.\u540d\u524d, \u90e8\u7f72.\u90e8\u7f72\u540d\r\nFROM \u793e\u54e1\r\nINNER JOIN \u90e8\u7f72\r\nON \u793e\u54e1.\u90e8\u7f72ID = \u90e8\u7f72.\u90e8\u7f72ID;<\/code><\/pre>\n<h3>\u4f8b\uff1a<\/h3>\n<p>\u300c\u793e\u54e1\u540d\u7c3f\u300d\u3068\u300c\u90e8\u7f72\u4e00\u89a7\u300d\u3092\u7167\u3089\u3057\u5408\u308f\u305b\u3066\u3001\u90e8\u7f72\u304c\u767b\u9332\u3055\u308c\u3066\u3044\u308b\u793e\u54e1\u3060\u3051\u3092\u8868\u793a\u3059\u308b\u611f\u3058\u3067\u3059\u3002<\/p>\n<hr>\n<h3>2. LEFT JOIN\uff08\u793e\u54e1\u5168\u54e1\u3092\u8868\u793a\u3001\u90e8\u7f72\u304c\u7121\u304f\u3066\u3082OK\uff09<\/h3>\n<p>\u5de6\u5074\uff08FROM\u3067\u6307\u5b9a\u3057\u305f\uff09\u30c6\u30fc\u30d6\u30eb\uff1d\u793e\u54e1\u30c6\u30fc\u30d6\u30eb\u306e\u3059\u3079\u3066\u306e\u60c5\u5831\u3092\u8868\u793a\u3057\u307e\u3059\u3002<\/p>\n<pre><code>SELECT \u793e\u54e1.\u540d\u524d, \u90e8\u7f72.\u90e8\u7f72\u540d\r\nFROM \u793e\u54e1\r\nLEFT JOIN \u90e8\u7f72\r\nON \u793e\u54e1.\u90e8\u7f72ID = \u90e8\u7f72.\u90e8\u7f72ID;<\/code><\/pre>\n<h3>\u4f8b\uff1a<\/h3>\n<p>\u5168\u793e\u54e1\u30ea\u30b9\u30c8\u3092\u30d9\u30fc\u30b9\u306b\u3057\u3066\u3001\u90e8\u7f72\u304c\u5206\u304b\u3063\u3066\u3044\u308b\u4eba\u306f\u90e8\u7f72\u540d\u3082\u8868\u793a\u3001\u90e8\u7f72\u304c\u672a\u767b\u9332\u306e\u4eba\u306f\u300c\u90e8\u7f72\u4e0d\u660e\u300d\u3068\u3057\u3066\u8868\u793a\u3059\u308b\u30a4\u30e1\u30fc\u30b8\u3067\u3059\u3002<\/p>\n<hr>\n<h3>3. RIGHT JOIN\uff08\u90e8\u7f72\u3092\u57fa\u6e96\u306b\u3059\u308b\uff09<\/h3>\n<p>\u53f3\u5074\uff08JOIN\u3057\u305f\uff09\u30c6\u30fc\u30d6\u30eb\uff1d\u90e8\u7f72\u30c6\u30fc\u30d6\u30eb\u306e\u3059\u3079\u3066\u306e\u60c5\u5831\u3092\u8868\u793a\u3057\u307e\u3059\u3002<\/p>\n<pre><code>SELECT \u793e\u54e1.\u540d\u524d, \u90e8\u7f72.\u90e8\u7f72\u540d\r\nFROM \u793e\u54e1\r\nRIGHT JOIN \u90e8\u7f72\r\nON \u793e\u54e1.\u90e8\u7f72ID = \u90e8\u7f72.\u90e8\u7f72ID;<\/code><\/pre>\n<h3>\u4f8b\uff1a<\/h3>\n<p>\u90e8\u7f72\u4e00\u89a7\u8868\u3092\u30d9\u30fc\u30b9\u306b\u3057\u3066\u3001\u3082\u3057\u793e\u54e1\u304c\u3044\u308c\u3070\u540d\u524d\u3092\u8868\u793a\u3059\u308b\u3051\u3069\u3001\u8ab0\u3082\u6240\u5c5e\u3057\u3066\u3044\u306a\u3044\u90e8\u7f72\u3067\u3082\u5fc5\u305a\u8868\u793a\u3059\u308b\u3001\u3068\u3044\u3046\u611f\u3058\u3067\u3059\u3002<\/p>\n<hr>\n<h3>4. OUTER JOIN\uff08\u4e21\u65b9\u306e\u5168\u60c5\u5831\u3092\u51fa\u3059\uff09<\/h3>\n<p>\u90e8\u7f72\u306b\u6240\u5c5e\u3057\u3066\u3044\u306a\u3044\u793e\u54e1\u3001\u793e\u54e1\u304c\u6240\u5c5e\u3057\u3066\u3044\u306a\u3044\u90e8\u7f72\u3001\u4e21\u65b9\u3068\u3082\u3059\u3079\u3066\u51fa\u3057\u305f\u3044\u3068\u304d\u3002<\/p>\n<pre><code>SELECT \u793e\u54e1.\u540d\u524d, \u90e8\u7f72.\u90e8\u7f72\u540d\r\nFROM \u793e\u54e1\r\nLEFT JOIN \u90e8\u7f72\r\nON \u793e\u54e1.\u90e8\u7f72ID = \u90e8\u7f72.\u90e8\u7f72ID\r\nUNION\r\nSELECT \u793e\u54e1.\u540d\u524d, \u90e8\u7f72.\u90e8\u7f72\u540d\r\nFROM \u793e\u54e1\r\nRIGHT JOIN \u90e8\u7f72\r\nON \u793e\u54e1.\u90e8\u7f72ID = \u90e8\u7f72.\u90e8\u7f72ID;<\/code><\/pre>\n<h3>\u4f8b\uff1a<\/h3>\n<p>\u793e\u54e1\u540d\u7c3f\u3068\u90e8\u7f72\u4e00\u89a7\u8868\u3092\u4e21\u65b9\u305d\u306e\u307e\u307e\u5168\u90e8\u8868\u793a\u3057\u3001\u4e0d\u660e\u306a\u3068\u3053\u308d\u306f\u7a7a\u767d\u3067\u51fa\u3059\u3001\u3068\u3044\u3046\u30a4\u30e1\u30fc\u30b8\u3067\u3059\u3002<\/p>\n<hr>\n<h2>\u3010\u767a\u5c55\u7de8\u3011\u8907\u6570\u30c6\u30fc\u30d6\u30eb\u3092JOIN\u3059\u308b\u30d1\u30bf\u30fc\u30f3<\/h2>\n<p>\u5b9f\u969b\u306e\u696d\u52d9\u3067\u306f\u30013\u3064\u4ee5\u4e0a\u306e\u30c6\u30fc\u30d6\u30eb\u3092\u7d50\u5408\u3059\u308b\u30b1\u30fc\u30b9\u3082\u3088\u304f\u3042\u308a\u307e\u3059\u3002<\/p>\n<p>\u4f8b\u3048\u3070\u3001\u6b21\u306e\u3088\u3046\u306a\u30c6\u30fc\u30d6\u30eb\u69cb\u6210\u3060\u3068\u3057\u307e\u3057\u3087\u3046\uff1a<\/p>\n<ul>\n<li>\n<p><strong>\u793e\u54e1\u30c6\u30fc\u30d6\u30eb<\/strong><\/p>\n<\/li>\n<li>\n<p><strong>\u90e8\u7f72\u30c6\u30fc\u30d6\u30eb<\/strong><\/p>\n<\/li>\n<li>\n<p><strong>\u52e4\u52d9\u5730\u30c6\u30fc\u30d6\u30eb<\/strong><\/p>\n<\/li>\n<\/ul>\n<p>\u793e\u54e1\u306f\u90e8\u7f72\u306b\u6240\u5c5e\u3057\u3001\u90e8\u7f72\u3054\u3068\u306b\u52e4\u52d9\u5730\u3082\u6c7a\u307e\u3063\u3066\u3044\u308b\u5834\u5408\u3001\u4ee5\u4e0b\u306e\u3088\u3046\u306bJOIN\u3057\u307e\u3059\u3002<\/p>\n<pre><code>SELECT \u793e\u54e1.\u540d\u524d, \u90e8\u7f72.\u90e8\u7f72\u540d, \u52e4\u52d9\u5730.\u52e4\u52d9\u5730\u540d\r\nFROM \u793e\u54e1\r\nINNER JOIN \u90e8\u7f72\r\nON \u793e\u54e1.\u90e8\u7f72ID = \u90e8\u7f72.\u90e8\u7f72ID\r\nINNER JOIN \u52e4\u52d9\u5730\r\nON \u90e8\u7f72.\u52e4\u52d9\u5730ID = \u52e4\u52d9\u5730.\u52e4\u52d9\u5730ID;<\/code><\/pre>\n<h3>\u4f8b\uff1a<\/h3>\n<p>\u300c\u793e\u54e1 \u2192 \u90e8\u7f72 \u2192 \u52e4\u52d9\u5730\u300d\u3068\u3001\u307e\u308b\u3067\u201c\u60c5\u5831\u30ea\u30ec\u30fc\u201d\u306e\u3088\u3046\u306bJOIN\u3092\u30d0\u30c8\u30f3\u30d1\u30b9\u3057\u3066\u3044\u304f\u30a4\u30e1\u30fc\u30b8\u3067\u3059\u3002<\/p>\n<p>\u3053\u306e\u3088\u3046\u306b\u3001JOIN\u306f2\u30c6\u30fc\u30d6\u30eb\u306b\u9650\u3089\u305a\u30013\u30c6\u30fc\u30d6\u30eb\u30014\u30c6\u30fc\u30d6\u30eb\u3068\u3001\u5fc5\u8981\u306a\u3060\u3051\u7e4b\u3044\u3067\u3044\u3051\u307e\u3059\u3002<\/p>\n<hr>\n<h2>JOIN\u306e\u4f7f\u3044\u5206\u3051\uff08\u8ff7\u3063\u305f\u3089\u3053\u308c\u3067\u6c7a\u3081\u3088\u3046\uff09<\/h2>\n<pre><code>+------------+--------------------------------------------+\r\n<span>| JOIN\u306e\u7a2e\u985e |<\/span> \u4f7f\u3046\u30b7\u30fc\u30f3                               <span>|\r\n+------------+--------------------------------------------+\r\n|<\/span> INNER JOIN <span>| \u90e8\u7f72\u306b\u6240\u5c5e\u3057\u3066\u3044\u308b\u793e\u54e1\u3060\u3051\u51fa\u3057\u305f\u3044        |<\/span>\r\n<span>| LEFT JOIN  |<\/span> \u5168\u793e\u54e1\u3092\u51fa\u3057\u3066\u3001\u90e8\u7f72\u672a\u767b\u9332\u8005\u3082\u62fe\u3044\u305f\u3044    <span>|\r\n|<\/span> RIGHT JOIN <span>| \u5168\u90e8\u7f72\u3092\u51fa\u3057\u3066\u3001\u7a7a\u304d\u90e8\u7f72\u3082\u78ba\u8a8d\u3057\u305f\u3044      |<\/span>\r\n<span>| OUTER JOIN |<\/span> \u793e\u54e1\u30fb\u90e8\u7f72\u3068\u3082\u306b\u3059\u3079\u3066\u8868\u793a\u3057\u305f\u3044           <span>|\r\n+------------+--------------------------------------------+<\/span><\/code><\/pre>\n<hr>\n<h2>\u5b9f\u8df5\uff1a\u90e8\u7f72\u5225\u306b\u793e\u54e1\u6570\u3092\u96c6\u8a08\u3059\u308b<\/h2>\n<p>\u8ab2\u984c\uff1a\u90e8\u7f72\u3054\u3068\u306e\u793e\u54e1\u6570\u3092\u51fa\u3057\u305f\u3044\uff08\u90e8\u7f72\u304c\u672a\u767b\u9332\u3067\u3082\u96c6\u8a08\u306b\u542b\u3081\u305f\u3044\uff09<\/p>\n<pre><code>SELECT \u90e8\u7f72.\u90e8\u7f72\u540d, COUNT(\u793e\u54e1.\u793e\u54e1ID) <span>AS<\/span> \u793e\u54e1\u6570\r\nFROM \u793e\u54e1\r\nLEFT JOIN \u90e8\u7f72\r\nON \u793e\u54e1.\u90e8\u7f72ID = \u90e8\u7f72.\u90e8\u7f72ID\r\nGROUP BY \u90e8\u7f72.\u90e8\u7f72\u540d;<\/code><\/pre>\n<h3>\u89e3\u8aac<\/h3>\n<p>LEFT JOIN\u3060\u304b\u3089\u3001\u90e8\u7f72\u672a\u767b\u9332\u306e\u793e\u54e1\u3082\u300c\u672a\u6240\u5c5e\u300d\u3068\u3057\u3066\u307e\u3068\u3081\u3066\u96c6\u8a08\u3067\u304d\u307e\u3059\u3002<\/p>\n<p>\u5b9f\u52d9\u3067\u306f\u3001\u3053\u3046\u3057\u305f\u300c\u629c\u3051\u6f0f\u308c\u9632\u6b62\u300d\u306e\u305f\u3081\u306bLEFT JOIN\u304c\u3088\u304f\u4f7f\u308f\u308c\u307e\u3059\u3002<\/p>\n<hr>\n<h2>\u3088\u304f\u3042\u308b\u8cea\u554f<\/h2>\n<p><strong>Q1. INNER JOIN\u3068LEFT JOIN\u3069\u3063\u3061\u3092\u4f7f\u3048\u3070\u826f\u3044\uff1f<\/strong> \u2192 \u5171\u901a\u30c7\u30fc\u30bf\u3060\u3051\u306a\u3089INNER JOIN\u3001\u629c\u3051\u3082\u62fe\u3044\u305f\u3051\u308c\u3070LEFT JOIN\u3002<\/p>\n<p><strong>Q2. RIGHT JOIN\u3063\u3066\u3042\u307e\u308a\u4f7f\u308f\u306a\u3044\uff1f<\/strong> \u2192 LEFT JOIN\u3092\u30c6\u30fc\u30d6\u30eb\u3092\u5165\u308c\u66ff\u3048\u3066\u4f7f\u3048\u3070\u307b\u307c\u4ee3\u7528\u3067\u304d\u307e\u3059\u3002<\/p>\n<p><strong>Q3. \u8907\u6570\u30c6\u30fc\u30d6\u30ebJOIN\u3063\u3066\u96e3\u3057\u304f\u306a\u3044\uff1f<\/strong> \u2192 \u30d0\u30c8\u30f3\u30ea\u30ec\u30fc\u306e\u3088\u3046\u306b1\u3064\u305a\u3064JOIN\u3057\u3066\u3044\u3051\u3070\u5927\u4e08\u592b\u3067\u3059\uff01<\/p>\n<hr>\n<h2>\u307e\u3068\u3081\uff5c\u307e\u305a\u306fINNER JOIN\u3068LEFT JOIN\u3092\u30de\u30b9\u30bf\u30fc\u3057\u3088\u3046<\/h2>\n<p>JOIN\u306f\u300c\u540d\u7c3f\u306e\u7167\u3089\u3057\u5408\u308f\u305b\u300d\u3068\u601d\u3048\u3070\u30a4\u30e1\u30fc\u30b8\u3057\u3084\u3059\u3044\u3067\u3059\u3002<\/p>\n<p>\u307e\u305a\u306fINNER JOIN\u3068LEFT JOIN\u306e\u4f7f\u3044\u5206\u3051\u3092\u30de\u30b9\u30bf\u30fc\u3059\u308b\u3068\u3053\u308d\u304b\u3089\u59cb\u3081\u307e\u3057\u3087\u3046\u3002<\/p>\n<p>\u3053\u308c\u304c\u5206\u304b\u308c\u3070\u3001\u5b9f\u969b\u306e\u73fe\u5834\u3067\u3082\u81ea\u5728\u306b\u30c7\u30fc\u30bf\u3092\u7d44\u307f\u5408\u308f\u305b\u308b\u529b\u304c\u8eab\u306b\u3064\u304d\u307e\u3059\u3002<\/p>\n<hr>\n<h3>\u3010\u5916\u90e8\u30ea\u30f3\u30af\u3011<\/h3>\n<p><a href=\"https:\/\/docs.oracle.com\/en\/database\/oracle\/oracle-database\/19\/sqlrf\/Joins.html\">SQL JOIN\uff08Oracle\u516c\u5f0f\uff09<\/a><\/p>\n<p><a href=\"https:\/\/www.postgresql.org\/docs\/current\/queries-table-expressions.html#QUERIES-JOIN\">SQL JOIN\uff08PostgreSQL\u516c\u5f0f\uff09<\/a><\/p>\n<h3>\u3010\u5185\u90e8\u30ea\u30f3\u30af\u3011<\/h3>\n<p><a href=\"https:\/\/route-zero.com\/recruit\/route\/989\/\">\u3010SQL\u3011\u526f\u554f\u3044\u5408\u308f\u305b\u5165\u9580\uff5c\u57fa\u672c\u69cb\u6587\u304b\u3089\u5b9f\u4f8b\u307e\u3067\u5fb9\u5e95\u89e3\u8aac<\/a><\/p>\n<\/div>\n","protected":false},"featured_media":1120,"template":"","_links":{"self":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route\/1119"}],"collection":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/route"}],"about":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/types\/route"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/media\/1120"}],"wp:attachment":[{"href":"https:\/\/route-zero.com\/recruit\/wp-json\/wp\/v2\/media?parent=1119"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}