{"id":42046,"date":"2023-04-12T14:51:28","date_gmt":"2023-09-22T20:15:39","guid":{"rendered":"https:\/\/www.silicloud.com\/zh\/blog\/%e5%9c%a8rails%e7%9a%84arel%e4%b8%ad%e5%8f%91%e7%94%9f%e4%ba%86postgresql-syntax%e9%94%99%e8%af%af\/"},"modified":"2024-04-29T23:09:42","modified_gmt":"2024-04-29T15:09:42","slug":"%e5%9c%a8rails%e7%9a%84arel%e4%b8%ad%e5%8f%91%e7%94%9f%e4%ba%86postgresql-syntax%e9%94%99%e8%af%af","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/zh\/blog\/%e5%9c%a8rails%e7%9a%84arel%e4%b8%ad%e5%8f%91%e7%94%9f%e4%ba%86postgresql-syntax%e9%94%99%e8%af%af\/","title":{"rendered":"\u5728Rails\u7684Arel\u4e2d\u53d1\u751f\u4e86PostgreSQL Syntax\u9519\u8bef"},"content":{"rendered":"<p>\u5982\u679c\u5728Rails\u4e2d\u4f7f\u7528Arel\u53d1\u51faSQL\u67e5\u8be2\uff0c\u5f53\u4f7f\u7528PostgreSQL\u7248\u672c9.2\u65f6\u4f1a\u51fa\u73b0\u9519\u8bef\u3002\u800c\u57289.4\u7248\u672c\u4e0b\u4e0d\u4f1a\u51fa\u9519\u3002<br \/>\n\u7531\u4e8e\u5728\u4f7f\u7528\u7684CI\u670d\u52a1\u4e0a\u7684PostgreSQL\u7248\u672c\u4e0d\u540c\uff0c\u53ef\u80fd\u4f1a\u5bfc\u81f4\u5728\u672c\u5730\u4e0d\u4f1a\u51fa\u9519\u7684\u60c5\u51b5\u4e0b\u5728CI\u4e0a\u51fa\u9519\uff0c\u8fd9\u4f1a\u5bfc\u81f4\u6df7\u4e71\uff0c\u6240\u4ee5\u505a\u4e2a\u5907\u5fd8\u5f55\u3002<\/p>\n<h4>\u9519\u8bef\u5185\u5bb9 (yu\u00e8 w\u00f9<\/h4>\n<pre class=\"post-pre\"><code>ActiveRecord::StatementInvalid:\r\n       PG::SyntaxError: ERROR:  syntax error at or near \"FROM\"\r\n       LINE 1: ...ions\".* FROM \"reservations\" WHERE (EXISTS (SELECT FROM \"stor...\r\n                                                                    ^\r\n       : SELECT \"reservations\".* FROM \"reservations\" WHERE (EXISTS (SELECT FROM \"stored_reservations\" WHERE \"reservations\".\"id\" = \"stored_reservations\".\"id\"))\r\n\r\n<\/code><\/pre>\n<h4>\u5728Rails\u7684\u6a21\u578b\u4e2d\u4f7f\u7528scope<\/h4>\n<p>\u6211\u4e4b\u524d\u7684\u63cf\u8ff0\u5982\u4e0b\u6240\u793a\u3002<\/p>\n<pre class=\"post-pre\"><code>  scope :exists_in_stored, -&gt; do\r\n    arel_stored_reservations = Stored::Reservation.arel_table\r\n\r\n    condition = reservations[:id].eq(arel_stored_reservations[:id])\r\n    where(arel_stored_reservations.where(condition).exists)\r\n  end\r\n<\/code><\/pre>\n<h4>SQL\u662f\u7528\u4e8e\u7ba1\u7406\u5173\u7cfb\u6570\u636e\u5e93\u7684\u7f16\u7a0b\u8bed\u8a00\u3002<\/h4>\n<p>Scope\u4e2d\u5305\u542b\u4ee5\u4e0bSQL\u67e5\u8be2\u3002<\/p>\n<pre class=\"post-pre\"><code>SELECT \"reservations\".* \r\nFROM \"reservations\" \r\nWHERE (EXISTS (\r\n    SELECT FROM \"stored_reservations\" \r\n    WHERE \"reservations\".\"id\" = \"stored_reservations\".\"id\")\r\n)\r\n<\/code><\/pre>\n<h4>\u5bfc\u81f4\u7684\u539f\u56e0\u662f\u4ec0\u4e48\uff1f<\/h4>\n<p>\u5f53\u5728EXISTS\u7684\u5185\u90e8SELECT\u4e4b\u540e\u51fa\u73b0FROM\u65f6\uff0c\u4f1a\u5bfc\u81f4\u8bed\u6cd5\u9519\u8bef\u3002<br \/>\n\u5728PostgreSQL\u7248\u672c\u4e3a9.2\u7684\u60c5\u51b5\u4e0b\u4f1a\u51fa\u73b0\u9519\u8bef\u3002<\/p>\n<h4>\u89e3\u51b3\u65b9\u6848 c\u00e8)<\/h4>\n<p>\u5c06scope\u7684\u63cf\u8ff0\u66f4\u6539\u4e3a\u4ee5\u4e0b\u5185\u5bb9\u3002<\/p>\n<pre class=\"post-pre\"><code>  scope :exists_in_stored, -&gt; do\r\n    arel_stored_reservations = Stored::Reservation.arel_table\r\n\r\n    condition = reservations[:id].eq(arel_stored_reservations[:id])\r\n    where(Stored::Reservation.where(condition).exists)\r\n  end\r\n<\/code><\/pre>\n<p>\u90a3\u4e48\uff0cSQL\u4f1a\u53d8\u6210\u4e0b\u9762\u8fd9\u6837\u3002<\/p>\n<pre class=\"post-pre\"><code>SELECT \"reservations\".* \r\nFROM \"reservations\" \r\nWHERE (EXISTS (\r\n    SELECT \"stored_reservations\".* FROM \"stored_reservations\" \r\n    WHERE \"reservations\".\"id\" = \"stored_reservations\".\"id\")\r\n)\r\n<\/code><\/pre>\n<p>\u8fd9\u6837\u7684\u8bdd\uff0c\u5373\u4f7f\u5728PostgreSQL9.2\u4e2d\u4e5f\u4e0d\u4f1a\u51fa\u9519\u3002<\/p>\n<p>\u987a\u4fbf\u63d0\u4e00\u4e0b\uff0c\u5728wercker\u4e0a\u6307\u5b9aPostgreSQL\u7248\u672c\u7684\u65b9\u6cd5\u662f\u5728wercker.yml\u6587\u4ef6\u4e2d\u6309\u7167\u4ee5\u4e0b\u65b9\u5f0f\u8fdb\u884c\u63cf\u8ff0\u3002<\/p>\n<h4>wercker.yml \u7684\u542b\u4e49\u662f\u4ec0\u4e48\uff1f<\/h4>\n<pre class=\"post-pre\"><code>box: wercker\/rvm\r\nno-response-timeout: 10\r\n\r\nservices:\r\n    # \u4f7f\u7528\u3067\u304d\u308bservice\u3092\u691c\u7d22\u3059\u308b\u306b\u306f\u4ee5\u4e0b\u3092\u53c2\u7167\r\n    # https:\/\/app.wercker.com\/#explore\/boxes\/search\/ \r\n    #- wercker\/postgresql\r\n    #- wercker\/postgresql@0.0.4\r\n    - wercker\/postgresql9.2@0.0.7\r\n    #- bolek-kurowski\/postgresql9.3@0.0.8\r\n    #- userminddeployer\/postgresql9.3@0.0.7-usermind-9.3-1\r\n    #- userminddeployer\/postgresql9.4@0.0.7-usermind-9.4-3\r\n\r\n    #- wercker\/redis@1.0.1\r\n    - wercker\/redis\r\nbuild:\r\n    steps:\r\n      - rvm-use:\r\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>\u5982\u679c\u5728Rails\u4e2d\u4f7f\u7528Arel\u53d1\u51faSQL\u67e5\u8be2\uff0c\u5f53\u4f7f\u7528PostgreSQL\u7248\u672c9.2\u65f6\u4f1a\u51fa\u73b0\u9519\u8bef\u3002\u800c\u57289.4\u7248\u672c [&hellip;]<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-42046","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>\u5728Rails\u7684Arel\u4e2d\u53d1\u751f\u4e86PostgreSQL Syntax\u9519\u8bef - Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/zh\/blog\/\u5728rails\u7684arel\u4e2d\u53d1\u751f\u4e86postgresql-syntax\u9519\u8bef\/\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"\u5728Rails\u7684Arel\u4e2d\u53d1\u751f\u4e86PostgreSQL Syntax\u9519\u8bef\" \/>\n<meta property=\"og:description\" content=\"\u5982\u679c\u5728Rails\u4e2d\u4f7f\u7528Arel\u53d1\u51faSQL\u67e5\u8be2\uff0c\u5f53\u4f7f\u7528PostgreSQL\u7248\u672c9.2\u65f6\u4f1a\u51fa\u73b0\u9519\u8bef\u3002\u800c\u57289.4\u7248\u672c [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/zh\/blog\/\u5728rails\u7684arel\u4e2d\u53d1\u751f\u4e86postgresql-syntax\u9519\u8bef\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - Silicon Cloud\" \/>\n<meta property=\"article:published_time\" content=\"2023-09-22T20:15:39+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-04-29T15:09:42+00:00\" \/>\n<meta name=\"author\" content=\"\u96c5, \u609f\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"\u96c5, \u609f\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.silicloud.com\/zh\/blog\/%e5%9c%a8rails%e7%9a%84arel%e4%b8%ad%e5%8f%91%e7%94%9f%e4%ba%86postgresql-syntax%e9%94%99%e8%af%af\/\",\"url\":\"https:\/\/www.silicloud.com\/zh\/blog\/%e5%9c%a8rails%e7%9a%84arel%e4%b8%ad%e5%8f%91%e7%94%9f%e4%ba%86postgresql-syntax%e9%94%99%e8%af%af\/\",\"name\":\"\u5728Rails\u7684Arel\u4e2d\u53d1\u751f\u4e86PostgreSQL Syntax\u9519\u8bef - 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