{"id":36,"date":"2025-07-16T10:41:35","date_gmt":"2025-07-16T02:41:35","guid":{"rendered":"https:\/\/www.hgfwq.com\/blog\/?p=36"},"modified":"2025-07-16T10:41:35","modified_gmt":"2025-07-16T02:41:35","slug":"%e5%9c%a8hive%e4%b8%ad%e5%a4%84%e7%90%86null%e5%80%bc%e6%b1%82%e5%92%8c%e7%9a%84%e5%9c%b0%e6%96%b9%e5%9c%a8%e5%93%aa%e9%87%8c%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/www.hgfwq.com\/blog\/36.html","title":{"rendered":"\u5728Hive\u4e2d\u5904\u7406NULL\u503c\u6c42\u548c\u7684\u5730\u65b9\u5728\u54ea\u91cc\uff1f"},"content":{"rendered":"\n<p><h1>Hive \u4e2d\u5904\u7406 NULL \u503c\u7684\u6c42\u548c\u64cd\u4f5c<\/h1>\n<\/p>\n<p style=\"text-align:center\"><img decoding=\"async\" src=\"https:\/\/www.hgfwq.com\/blog\/wp-content\/uploads\/2025\/07\/BhXGfvAt7.jpg\" alt=\"\u5728Hive\u4e2d\u5904\u7406NULL\u503c\u6c42\u548c\u7684\u5730\u65b9\u5728\u54ea\u91cc\uff1f\" title=\"\u5728Hive\u4e2d\u5904\u7406NULL\u503c\u6c42\u548c\u7684\u5730\u65b9\u5728\u54ea\u91cc\uff1f\"><\/p>\n<p>    <!-- \u5168\u7bc7\u7cbe\u534e --><\/p>\n<p><p>\u5728Hive\u4e2d\u8fdb\u884c\u6570\u636e\u6c42\u548c\u65f6\uff0c\u5e38\u5e38\u4f1a\u9047\u5230\u5305\u542bNULL\u503c\u7684\u5b57\u6bb5\uff0c\u8fd9\u4e9bNULL\u503c\u4f1a\u5bf9\u6c42\u548c\u7ed3\u679c\u4ea7\u751f\u5f71\u54cd\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecd\u5728Hive\u4e2d\u5982\u4f55\u6b63\u786e\u5904\u7406\u5305\u542bNULL\u503c\u7684\u5b57\u6bb5\u6c42\u548c\u64cd\u4f5c\uff0c\u5e76\u901a\u8fc7\u5b9e\u4f8b\u6f14\u793a\u5982\u4f55\u4f7f\u7528\u4e0d\u540c\u7684\u65b9\u6cd5\u6765\u786e\u4fdd\u6c42\u548c\u7ed3\u679c\u7684\u51c6\u786e\u6027\u3002<\/p>\n<\/p>\n<p>    <!-- \u7b2c\u4e00\u6bb5\uff1a\u4ecb\u7ecd\u80cc\u666f\u548c\u95ee\u9898 --><\/p>\n<p><p>\u968f\u7740\u5927\u6570\u636e\u65f6\u4ee3\u7684\u5230\u6765\uff0cHive\u4f5c\u4e3aHadoop\u751f\u6001\u7cfb\u7edf\u4e2d\u7684\u4e00\u4e2a\u91cd\u8981\u5de5\u5177\uff0c\u88ab\u5e7f\u6cdb\u5e94\u7528\u4e8e\u5927\u6570\u636e\u5904\u7406\u548c\u5206\u6790\u3002\u5728Hive\u4e2d\uff0c\u5bf9\u6570\u636e\u8fdb\u884c\u6c42\u548c\u64cd\u4f5c\u662f\u4e00\u9879\u5e38\u89c1\u7684\u64cd\u4f5c\uff0c\u4f46\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u6570\u636e\u5f80\u5f80\u5305\u542bNULL\u503c\u3002\u5982\u679c\u4e0d\u6b63\u786e\u5904\u7406\u8fd9\u4e9bNULL\u503c\uff0c\u53ef\u80fd\u4f1a\u5bfc\u81f4\u6c42\u548c\u7ed3\u679c\u7684\u504f\u5dee\u3002\u56e0\u6b64\uff0c\u5982\u4f55\u6709\u6548\u5904\u7406\u5305\u542bNULL\u503c\u7684\u5b57\u6bb5\u6c42\u548c\u662fHive\u64cd\u4f5c\u4e2d\u7684\u4e00\u4e2a\u5173\u952e\u95ee\u9898\u3002<\/p>\n<\/p>\n<p>    <!-- \u7b2c\u4e8c\u6bb5\uff1aHive\u4e2d\u7684\u6c42\u548c\u64cd\u4f5c --><\/p>\n<p><p>Hive\u63d0\u4f9b\u4e86\u591a\u79cd\u6c42\u548c\u51fd\u6570\uff0c\u5982`SUM()`\uff0c\u7528\u4e8e\u8ba1\u7b97\u5b57\u6bb5\u7684\u52a0\u6743\u548c\u3002\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0c\u5982\u679c\u5b57\u6bb5\u4e2d\u5305\u542bNULL\u503c\uff0c`SUM()`\u51fd\u6570\u4f1a\u5c06\u5176\u5ffd\u7565\u3002\u4f46\u662f\uff0c\u6709\u65f6\u6211\u4eec\u9700\u8981\u8003\u8651NULL\u503c\u5bf9\u6c42\u548c\u7ed3\u679c\u7684\u5f71\u54cd\u3002<\/p>\n<\/p>\n<p>    <!-- \u7b2c\u4e09\u6bb5\uff1a\u5904\u7406NULL\u503c\u7684\u65b9\u6cd5 --><\/p>\n<p><p>\u5728Hive\u4e2d\u5904\u7406NULL\u503c\u8fdb\u884c\u6c42\u548c\u64cd\u4f5c\uff0c\u4e3b\u8981\u6709\u4ee5\u4e0b\u51e0\u79cd\u65b9\u6cd5\uff1a<\/p>\n<\/p>\n<p>    <!-- \u7b2c\u56db\u6bb5\uff1a\u4f7f\u7528 COALESCE \u51fd\u6570 --><\/p>\n<p><p>\u4f7f\u7528`COALESCE`\u51fd\u6570\u53ef\u4ee5\u5c06NULL\u503c\u8f6c\u6362\u4e3a0\uff0c\u7136\u540e\u518d\u8fdb\u884c\u6c42\u548c\u64cd\u4f5c\u3002`COALESCE`\u51fd\u6570\u4f1a\u8fd4\u56de\u53c2\u6570\u5217\u8868\u4e2d\u7684\u7b2c\u4e00\u4e2a\u975eNULL\u503c\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n<\/p>\n<p><pre><\/p>\r\n<p>    SELECT SUM(COALESCE(column_name, 0)) FROM table_name;<\/p>\r\n<p>    <\/pre>\n<\/p>\n<p>    <!-- \u7b2c\u4e94\u6bb5\uff1a\u4f7f\u7528 IFNULL \u51fd\u6570 --><\/p>\n<p><p>`IFNULL`\u51fd\u6570\u4e0e`COALESCE`\u7c7b\u4f3c\uff0c\u4f46\u53ea\u63a5\u53d7\u4e24\u4e2a\u53c2\u6570\u3002\u5982\u679c\u7b2c\u4e00\u4e2a\u53c2\u6570\u662fNULL\uff0c\u5219\u8fd4\u56de\u7b2c\u4e8c\u4e2a\u53c2\u6570\u7684\u503c\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n<\/p>\n<p><pre><\/p>\r\n<p>    SELECT SUM(IFNULL(column_name, 0)) FROM table_name;<\/p>\r\n<p>    <\/pre>\n<\/p>\n<p>    <!-- \u7b2c\u516d\u6bb5\uff1a\u4f7f\u7528 CASE \u8bed\u53e5 --><\/p>\n<p><p>\u4f7f\u7528`CASE`\u8bed\u53e5\u53ef\u4ee5\u66f4\u7075\u6d3b\u5730\u5904\u7406NULL\u503c\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\uff0c\u5176\u4e2d\u53ea\u6709\u5f53`column_name`\u4e0d\u662fNULL\u65f6\u624d\u5c06\u5176\u5305\u542b\u5728\u6c42\u548c\u4e2d\uff1a<\/p>\n<\/p>\n<p><pre><\/p>\r\n<p>    SELECT SUM(column_name) AS total_sum<\/p>\r\n<p>    FROM table_name<\/p>\r\n<p>    WHERE column_name IS NOT NULL;<\/p>\r\n<p>    <\/pre>\n<\/p>\n<p>    <!-- \u7b2c\u4e03\u6bb5\uff1a\u5904\u7406\u4e0d\u540c\u7684\u6570\u636e\u7c7b\u578b --><\/p>\n<p><p>\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0c\u53ef\u80fd\u9700\u8981\u5bf9\u4e0d\u540c\u6570\u636e\u7c7b\u578b\u7684\u5b57\u6bb5\u8fdb\u884c\u6c42\u548c\uff0c\u8fd9\u65f6\u9700\u8981\u786e\u4fdd\u6570\u636e\u7c7b\u578b\u7684\u4e00\u81f4\u6027\u3002\u53ef\u4ee5\u4f7f\u7528Hive\u7684\u7c7b\u578b\u8f6c\u6362\u51fd\u6570\uff0c\u5982`CAST`\uff0c\u6765\u8f6c\u6362\u6570\u636e\u7c7b\u578b\u3002\u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n<\/p>\n<p><pre><\/p>\r\n<p>    SELECT SUM(CAST(column_name AS DOUBLE)) FROM table_name;<\/p>\r\n<p>    <\/pre>\n<\/p>\n<p>    <!-- \u7b2c\u516b\u6bb5\uff1a\u6ce8\u610f\u4e8b\u9879 --><\/p>\n<p><p>\u5728\u4f7f\u7528\u4e0a\u8ff0\u65b9\u6cd5\u65f6\uff0c\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n<\/p>\n<ul>\n<li>\u786e\u4fddNULL\u503c\u7684\u5904\u7406\u903b\u8f91\u7b26\u5408\u4e1a\u52a1\u9700\u6c42\u3002<\/li>\n<li>\u5bf9\u4e8e\u4e0d\u540c\u7684\u6570\u636e\u7c7b\u578b\uff0c\u786e\u4fdd\u5728\u8fdb\u884c\u6c42\u548c\u64cd\u4f5c\u524d\u8fdb\u884c\u9002\u5f53\u7684\u7c7b\u578b\u8f6c\u6362\u3002<\/li>\n<li>\u5728\u5927\u578b\u6570\u636e\u96c6\u4e0a\u8fdb\u884c\u64cd\u4f5c\u65f6\uff0c\u8003\u8651\u6027\u80fd\u548c\u8d44\u6e90\u6d88\u8017\u3002<\/li>\n<\/ul>\n<p>    <!-- \u95ee\u7b54\u5f0f\u6bb5\u843d --><\/p>\n<p><h2>\u5e38\u89c1\u95ee\u9898\u89e3\u7b54<\/h2>\n<\/p>\n<p><p><strong>Q1\uff1a\u4e3a\u4ec0\u4e48\u9700\u8981\u5904\u7406NULL\u503c\u8fdb\u884c\u6c42\u548c\u64cd\u4f5c\uff1f<\/strong><\/p>\n<\/p>\n<p><p>A1\uff1a\u5728\u6570\u636e\u5206\u6790\u4e2d\uff0cNULL\u503c\u8868\u793a\u7f3a\u5931\u6570\u636e\u3002\u5982\u679c\u4e0d\u5904\u7406NULL\u503c\uff0c\u53ef\u80fd\u4f1a\u5bfc\u81f4\u6c42\u548c\u7ed3\u679c\u4e0d\u51c6\u786e\uff0c\u5f71\u54cd\u5206\u6790\u7684\u53ef\u9760\u6027\u3002<\/p>\n<\/p>\n<p><p><strong>Q2\uff1aCOALESCE\u548cIFNULL\u6709\u4ec0\u4e48\u533a\u522b\uff1f<\/strong><\/p>\n<\/p>\n<p><p>A2\uff1a`COALESCE`\u53ef\u4ee5\u63a5\u53d7\u591a\u4e2a\u53c2\u6570\uff0c\u8fd4\u56de\u7b2c\u4e00\u4e2a\u975eNULL\u503c\uff1b\u800c`IFNULL`\u53ea\u63a5\u53d7\u4e24\u4e2a\u53c2\u6570\uff0c\u5982\u679c\u7b2c\u4e00\u4e2a\u53c2\u6570\u662fNULL\uff0c\u5219\u8fd4\u56de\u7b2c\u4e8c\u4e2a\u53c2\u6570\u3002<\/p>\n<\/p>\n<p><p><strong>Q3\uff1a\u5728Hive\u4e2d\u5982\u4f55\u5904\u7406\u5927\u6570\u636e\u91cf\u4e0b\u7684NULL\u503c\u6c42\u548c\uff1f<\/strong><\/p>\n<\/p>\n<p><p>A3\uff1a\u5728\u5904\u7406\u5927\u6570\u636e\u91cf\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528Hive\u7684\u5206\u5e03\u5f0f\u8ba1\u7b97\u80fd\u529b\uff0c\u786e\u4fdd\u6570\u636e\u5728\u591a\u4e2a\u8282\u70b9\u4e0a\u8fdb\u884c\u5e76\u884c\u5904\u7406\uff0c\u4ee5\u51cf\u5c11\u5355\u70b9\u74f6\u9888\u3002<\/p>\n<\/p>\n<p>    <!-- \u603b\u7ed3 --><\/p>\n<p><p>\u603b\u7ed3\u6765\u8bf4\uff0c\u5728Hive\u4e2d\u8fdb\u884c\u5305\u542bNULL\u503c\u7684\u5b57\u6bb5\u6c42\u548c\u64cd\u4f5c\u65f6\uff0c\u53ef\u4ee5\u6839\u636e\u5b9e\u9645\u9700\u6c42\u548c\u6570\u636e\u7279\u70b9\u9009\u62e9\u5408\u9002\u7684\u65b9\u6cd5\u3002\u5408\u7406\u5904\u7406NULL\u503c\u5bf9\u4e8e\u4fdd\u8bc1\u6570\u636e\u5206\u6790\u7684\u51c6\u786e\u6027\u81f3\u5173\u91cd\u8981\u3002\u901a\u8fc7\u672c\u6587\u7684\u4ecb\u7ecd\uff0c\u5e0c\u671b\u8bfb\u8005\u80fd\u591f\u66f4\u597d\u5730\u7406\u89e3Hive\u4e2d\u7684\u6c42\u548c\u64cd\u4f5c\uff0c\u5e76\u80fd\u591f\u5728\u5b9e\u9645\u5de5\u4f5c\u4e2d\u7075\u6d3b\u8fd0\u7528\u3002<\/p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Hive \u4e2d\u5904\u7406 NULL \u503c\u7684\u6c42\u548c\u64cd\u4f5c \u5728Hive\u4e2d\u8fdb\u884c\u6570\u636e\u6c42\u548c\u65f6\uff0c\u5e38\u5e38\u4f1a\u9047\u5230\u5305\u542bNULL\u503c\u7684\u5b57\u6bb5\uff0c\u8fd9\u4e9bNULL\u503c\u4f1a\u5bf9\u6c42\u548c\u7ed3\u679c\u4ea7\u751f\u5f71\u54cd\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecd\u5728Hive\u4e2d\u5982\u4f55\u6b63\u786e\u5904\u7406\u5305\u542bNULL\u503c\u7684\u5b57\u6bb5\u6c42\u548c\u64cd\u4f5c\uff0c\u5e76\u901a\u8fc7\u5b9e\u4f8b\u6f14\u793a\u5982\u4f55\u4f7f\u7528\u4e0d\u540c\u7684\u65b9\u6cd5\u6765&#8230;<\/p>\n","protected":false},"author":1,"featured_media":37,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[21,22,23],"topic":[],"class_list":["post-36","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-haiwai","tag-hive","tag-null","tag-23"],"_links":{"self":[{"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/posts\/36","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/comments?post=36"}],"version-history":[{"count":1,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/posts\/36\/revisions"}],"predecessor-version":[{"id":39,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/posts\/36\/revisions\/39"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/media\/37"}],"wp:attachment":[{"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/media?parent=36"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/categories?post=36"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/tags?post=36"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/www.hgfwq.com\/blog\/wp-json\/wp\/v2\/topic?post=36"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}