{"id":200527,"date":"2025-05-06T11:40:45","date_gmt":"2025-05-06T03:40:45","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200527\/"},"modified":"2025-05-06T11:40:45","modified_gmt":"2025-05-06T03:40:45","slug":"java-mybatis-%e6%9f%a5%e8%af%a2-sql-%e8%bf%94%e5%9b%9e-int-%e4%b8%ba-null-%e5%a6%82%e4%bd%95%e5%a4%84%e7%90%86%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200527\/","title":{"rendered":"Java MyBatis \u67e5\u8be2 SQL \u8fd4\u56de int \u4e3a Null \u5982\u4f55\u5904\u7406\uff1f"},"content":{"rendered":"

<\/b> <\/p>\n

Java MyBatis \u67e5\u8be2 SQL \u8fd4\u56de int \u4e3a Null \u5982\u4f55\u5904\u7406\uff1f<\/h1>\n

\u4e00\u5206\u8015\u8018\uff0c\u4e00\u5206\u6536\u83b7\uff01\u65e2\u7136\u6253\u5f00\u4e86\u8fd9\u7bc7\u6587\u7ae0\uff0c\u5c31\u575a\u6301\u770b\u4e0b\u53bb\u5427\uff01\u6587\u4e2d\u5185\u5bb9\u5305\u542b\u7b49\u7b49\u77e5\u8bc6\u70b9…\u5e0c\u671b\u4f60\u80fd\u5728\u9605\u8bfb\u672c\u6587\u540e\uff0c\u80fd\u771f\u771f\u5b9e\u5b9e\u5b66\u5230\u77e5\u8bc6\u6216\u8005\u5e2e\u4f60\u89e3\u51b3\u5fc3\u4e2d\u7684\u7591\u60d1\uff0c\u4e5f\u6b22\u8fce\u5927\u4f6c\u6216\u8005\u65b0\u4eba\u670b\u53cb\u4eec\u591a\u7559\u8a00\u8bc4\u8bba\uff0c\u591a\u7ed9\u5efa\u8bae\uff01\u8c22\u8c22\uff01<\/p>\n

<\/p>\n

java\u67e5\u8be2sql\u65f6\u8fd4\u56deint\u4e3anull\u7684\u5904\u7406<\/strong><\/p>\n

\u5f53\u4f7f\u7528mybatis\u67e5\u8be2sql\u8bed\u53e5\u65f6\uff0c\u5982\u679c\u671f\u671b\u8fd4\u56de\u4e00\u4e2aint\u503c\uff0c\u4f46\u5b9e\u9645\u8fd4\u56de\u4e86\u4e00\u4e2anull\u503c\uff0c\u4f1a\u5bfc\u81f4\u5f02\u5e38\u3002<\/p>\n

\u4ee5\u4e0b\u7ed9\u51fa\u4e24\u79cd\u53ef\u80fd\u7684\u89e3\u51b3\u65b9\u6848\uff1a<\/p>\n

    \n
  1. \u4fee\u6539\u8fd4\u56de\u503c\u7c7b\u578b<\/strong><\/li>\n<\/ol>\n

    \u5c06\u67e5\u8be2\u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u7c7b\u578b\u4eceint\u4fee\u6539\u4e3ainteger\uff0c\u8fd9\u6837\u5373\u4f7f\u6570\u636e\u5e93\u4e2d\u6ca1\u6709\u6570\u636e\u4e5f\u4e0d\u4f1a\u629b\u51fa\u5f02\u5e38\u3002\u5728\u4e1a\u52a1\u4ee3\u7801\u4e2d\uff0c\u53ef\u4ee5\u68c0\u67e5\u8fd4\u56de\u7684integer\u503c\u662f\u5426\u4e3anull\uff0c\u5c06\u5176\u8f6c\u6362\u4e3a0\u6216\u5176\u4ed6\u9ed8\u8ba4\u503c\u3002<\/p>\n

    @select(\"select max(id) from user\")\ninteger maxid();<\/pre>\n
      \n
    1. \u4f7f\u7528\u6570\u636e\u5e93\u51fd\u6570<\/strong><\/li>\n<\/ol>\n
      \u5728sql\u8bed\u53e5\u4e2d\u4f7f\u7528\u6570\u636e\u5e93\u51fd\u6570\uff0c\u5982ifnull\u6216coalesce\uff0c\u6765\u5904\u7406null\u503c\u3002\u4f8b\u5982\uff1a<\/p>\n
      @Select(\"SELECT max(id) FROM user\")\n@Options(resultType = int.class, useGeneratedKeys = true)\nint maxIdWithJdbc();<\/pre>\n
      sql\u8bed\u53e5\u4e2d\u4f7f\u7528ifnull(max(id), 0)\u8868\u8fbe\u5f0f\uff0c\u8fd9\u6837\u5982\u679c\u6ca1\u6709\u6570\u636e\uff0c\u5c06\u8fd4\u56de0\uff0c\u800c\u4e0d\u662fnull\u503c\u3002<\/p>\n
      \u4eca\u5929\u5173\u4e8e\u300aJava MyBatis \u67e5\u8be2 SQL \u8fd4\u56de int \u4e3a Null \u5982\u4f55\u5904\u7406\uff1f\u300b\u7684\u5185\u5bb9\u4ecb\u7ecd\u5c31\u5230\u6b64\u7ed3\u675f\uff0c\u5982\u679c\u6709\u4ec0\u4e48\u7591\u95ee\u6216\u8005\u5efa\u8bae\uff0c\u53ef\u4ee5\u5728\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u4e0b\u591a\u591a\u56de\u590d\u4ea4\u6d41\uff1b\u6587\u4e2d\u82e5\u6709\u4e0d\u6b63\u4e4b\u5904\uff0c\u4e5f\u5e0c\u671b\u56de\u590d\u7559\u8a00\u4ee5\u544a\u77e5\uff01<\/p>\n
      \n
      \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
      Java MyBatis \u67e5\u8be2 ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-200527","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200527","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=200527"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200527\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200527"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200527"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200527"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}