{"id":200001,"date":"2025-05-06T09:30:15","date_gmt":"2025-05-06T01:30:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200001\/"},"modified":"2025-05-06T09:30:15","modified_gmt":"2025-05-06T01:30:15","slug":"%e6%8e%8f%e6%8e%a2oracle-nvl%e5%87%bd%e6%95%b0%e7%9a%84%e5%a4%9a%e7%a7%8d%e5%ba%94%e7%94%a8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200001\/","title":{"rendered":"\u638f\u63a2Oracle NVL\u51fd\u6570\u7684\u591a\u79cd\u5e94\u7528"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>\u638f\u63a2Oracle NVL\u51fd\u6570\u7684\u591a\u79cd\u5e94\u7528<\/h1>\n<p>\u5c0f\u4f19\u4f34\u4eec\u5bf9\u6570\u636e\u5e93\u7f16\u7a0b\u611f\u5174\u8da3\u5417\uff1f\u662f\u5426\u6b63\u5728\u5b66\u4e60\u76f8\u5173\u77e5\u8bc6\u70b9\uff1f\u5982\u679c\u662f\uff0c\u90a3\u4e48\u672c\u6587\u300a\u638f\u63a2Oracle NVL\u51fd\u6570\u7684\u591a\u79cd\u5e94\u7528\u300b\uff0c\u5c31\u5f88\u9002\u5408\u4f60\uff0c\u672c\u7bc7\u6587\u7ae0\u8bb2\u89e3\u7684\u77e5\u8bc6\u70b9\u4e3b\u8981\u5305\u62ec\u3002\u5728\u4e4b\u540e\u7684\u6587\u7ae0\u4e2d\u4e5f\u4f1a\u591a\u591a\u5206\u4eab\u76f8\u5173\u77e5\u8bc6\u70b9\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff01<\/p>\n<p>Oracle\u6570\u636e\u5e93\u4e2d\u7684NVL\u51fd\u6570\u662f\u4e00\u79cd\u5e38\u7528\u7684\u5904\u7406\u7a7a\u503c\u7684\u51fd\u6570\uff0c\u5b83\u7684\u4f5c\u7528\u662f\u5224\u65ad\u6307\u5b9a\u7684\u8868\u8fbe\u5f0f\u662f\u5426\u4e3aNULL\uff0c\u82e5\u4e3a\u7a7a\u5219\u8fd4\u56de\u4e00\u4e2a\u6307\u5b9a\u7684\u9ed8\u8ba4\u503c\uff0c\u82e5\u4e0d\u4e3a\u7a7a\u5219\u8fd4\u56de\u539f\u59cb\u503c\u3002\u5728\u5b9e\u9645\u7684\u6570\u636e\u5e93\u5f00\u53d1\u4e2d\uff0c\u7075\u6d3b\u8fd0\u7528NVL\u51fd\u6570\u53ef\u4ee5\u6709\u6548\u5730\u5904\u7406\u6570\u636e\u4e3a\u7a7a\u7684\u60c5\u51b5\uff0c\u63d0\u9ad8\u4ee3\u7801\u7684\u5065\u58ee\u6027\u548c\u7a33\u5b9a\u6027\u3002\u672c\u6587\u5c06\u6df1\u5165\u63a2\u8ba8Oracle NVL\u51fd\u6570\u7684\u7075\u6d3b\u8fd0\u7528\uff0c\u5e76\u901a\u8fc7\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u8fdb\u884c\u8bf4\u660e\u3002<\/p>\n<h3>1. NVL\u51fd\u6570\u7684\u57fa\u672c\u7528\u6cd5<\/h3>\n<p>NVL\u51fd\u6570\u7684\u57fa\u672c\u8bed\u6cd5\u4e3a\uff1aNVL(expr1, expr2)\uff0c\u5176\u4e2dexpr1\u662f\u5f85\u5224\u65ad\u7684\u8868\u8fbe\u5f0f\uff0c\u5982\u679c\u4e3aNULL\u5219\u8fd4\u56deexpr2\uff0c\u5426\u5219\u8fd4\u56deexpr1\u3002<\/p>\n<p>\u4e3e\u4e2a\u7b80\u5355\u7684\u4f8b\u5b50\uff0c\u5047\u8bbe\u6709\u4e00\u4e2a\u5458\u5de5\u8868emp\uff0c\u5176\u4e2d\u6709\u4e00\u4e2a\u5b57\u6bb5salary\u8868\u793a\u5458\u5de5\u7684\u5de5\u8d44\uff0c\u5982\u679c\u67d0\u4e9b\u5458\u5de5\u7684\u5de5\u8d44\u4e3a\u7a7a\uff0c\u53ef\u4ee5\u4f7f\u7528NVL\u51fd\u6570\u7ed9\u4ed6\u4eec\u6307\u5b9a\u4e00\u4e2a\u9ed8\u8ba4\u503c\uff1a<\/p>\n<pre>SELECT emp_name, NVL(salary, 0) AS salary\nFROM emp;<\/pre>\n<p>\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u5982\u679c\u67d0\u4e2a\u5458\u5de5\u7684\u5de5\u8d44\u4e3aNULL\uff0cNVL\u51fd\u6570\u4f1a\u5c06\u5176\u66ff\u6362\u4e3a0\uff0c\u4fdd\u8bc1\u67e5\u8be2\u7ed3\u679c\u4e2d\u4e0d\u4f1a\u51fa\u73b0\u7a7a\u503c\u3002<\/p>\n<h3>2. NVL\u51fd\u6570\u7684\u5d4c\u5957\u8fd0\u7528<\/h3>\n<p>NVL\u51fd\u6570\u4e5f\u53ef\u4ee5\u8fdb\u884c\u5d4c\u5957\u8fd0\u7528\uff0c\u5b9e\u73b0\u66f4\u52a0\u590d\u6742\u7684\u903b\u8f91\u5904\u7406\u3002\u4f8b\u5982\uff0c\u5047\u8bbe\u5458\u5de5\u8868emp\u4e2d\u6709\u4e00\u4e2a\u5b57\u6bb5bonus\u8868\u793a\u5458\u5de5\u7684\u5956\u91d1\uff0c\u5982\u679c\u4e00\u4e2a\u5458\u5de5\u7684\u5956\u91d1\u4e3a\u7a7a\uff0c\u53ef\u4ee5\u901a\u8fc7\u5d4c\u5957NVL\u51fd\u6570\u7ed9\u4ed6\u4eec\u6307\u5b9a\u4e0d\u540c\u7684\u9ed8\u8ba4\u503c\uff1a<\/p>\n<pre>SELECT emp_name, NVL(NVL(bonus, 0) * 1.1, 0) AS total_bonus\nFROM emp;<\/pre>\n<p>\u5728\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u5982\u679c\u4e00\u4e2a\u5458\u5de5\u7684\u5956\u91d1\u4e3a\u7a7a\uff0c\u9996\u5148\u4f1a\u88ab\u66ff\u6362\u4e3a0\uff0c\u7136\u540e\u518d\u4e58\u4ee51.1\uff0c\u6700\u540e\u5373\u4f7f\u8fd8\u662f\u4e3a\u7a7a\uff0c\u4e5f\u4f1a\u5c06\u5176\u66ff\u6362\u4e3a0\u3002\u8fd9\u6837\u5c31\u4fdd\u8bc1\u4e86\u5373\u4f7f\u5956\u91d1\u4e3a\u7a7a\uff0c\u4e5f\u4e0d\u4f1a\u5f71\u54cd\u6700\u7ec8\u7684\u8ba1\u7b97\u7ed3\u679c\u3002<\/p>\n<h3>3. NVL\u51fd\u6570\u7684\u7ec4\u5408\u8fd0\u7528<\/h3>\n<p>NVL\u51fd\u6570\u8fd8\u53ef\u4ee5\u548c\u5176\u4ed6\u51fd\u6570\u7ed3\u5408\u4f7f\u7528\uff0c\u5b9e\u73b0\u66f4\u52a0\u7075\u6d3b\u7684\u6570\u636e\u5904\u7406\u3002\u4f8b\u5982\uff0c\u5047\u8bbe\u5458\u5de5\u8868emp\u4e2d\u6709\u4e00\u4e2a\u5b57\u6bb5hire_date\u8868\u793a\u5458\u5de5\u7684\u5165\u804c\u65e5\u671f\uff0c\u5982\u679c\u67d0\u4e9b\u5458\u5de5\u7684\u5165\u804c\u65e5\u671f\u4e3a\u7a7a\uff0c\u53ef\u4ee5\u901a\u8fc7\u7ec4\u5408NVL\u548cTO_DATE\u51fd\u6570\u6765\u8bbe\u7f6e\u9ed8\u8ba4\u503c\uff1a<\/p>\n<pre>SELECT emp_name, NVL(TO_DATE(hire_date, 'YYYY-MM-DD'), TO_DATE('2021-01-01', 'YYYY-MM-DD')) AS hire_date\nFROM emp;<\/pre>\n<p>\u5728\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u5982\u679c\u5458\u5de5\u7684\u5165\u804c\u65e5\u671f\u4e3a\u7a7a\uff0cNVL\u51fd\u6570\u4f1a\u5c06\u5176\u66ff\u6362\u4e3a\u6307\u5b9a\u7684\u9ed8\u8ba4\u65e5\u671f&#8217;2021-01-01&#8217;\uff0c\u5e76\u8f6c\u6362\u4e3a\u65e5\u671f\u7c7b\u578b\uff0c\u4fdd\u8bc1\u6570\u636e\u7684\u5b8c\u6574\u6027\u548c\u51c6\u786e\u6027\u3002<\/p>\n<h3>\u7ed3\u8bed<\/h3>\n<p>\u901a\u8fc7\u4ee5\u4e0a\u7684\u4f8b\u5b50\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230Oracle NVL\u51fd\u6570\u7684\u7075\u6d3b\u8fd0\u7528\u53ef\u4ee5\u5e2e\u52a9\u6211\u4eec\u5904\u7406\u6570\u636e\u4e3a\u7a7a\u7684\u60c5\u51b5\uff0c\u63d0\u9ad8\u6570\u636e\u5904\u7406\u7684\u6548\u7387\u548c\u51c6\u786e\u6027\u3002\u5728\u5b9e\u9645\u7684\u6570\u636e\u5e93\u5f00\u53d1\u4e2d\uff0c\u5408\u7406\u5730\u8fd0\u7528NVL\u51fd\u6570\u80fd\u591f\u8ba9\u6211\u4eec\u7684\u4ee3\u7801\u66f4\u52a0\u5065\u58ee\uff0c\u540c\u65f6\u4e5f\u66f4\u52a0\u65b9\u4fbf\u7ef4\u62a4\u548c\u8c03\u8bd5\u3002\u5e0c\u671b\u672c\u6587\u7684\u5185\u5bb9\u80fd\u591f\u5e2e\u52a9\u8bfb\u8005\u66f4\u6df1\u5165\u5730\u7406\u89e3\u548c\u8fd0\u7528Oracle NVL\u51fd\u6570\u3002<\/p>\n<p>\u4eca\u5929\u5173\u4e8e\u300a\u638f\u63a2Oracle NVL\u51fd\u6570\u7684\u591a\u79cd\u5e94\u7528\u300b\u7684\u5185\u5bb9\u5c31\u4ecb\u7ecd\u5230\u8fd9\u91cc\u4e86\uff0c\u662f\u4e0d\u662f\u5b66\u8d77\u6765\u4e00\u76ee\u4e86\u7136\uff01\u60f3\u8981\u4e86\u89e3\u66f4\u591a\u5173\u4e8eOracle,\u7075\u6d3b\u8fd0\u7528,NVL\u51fd\u6570\u7684\u5185\u5bb9\u8bf7\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>\u638f\u63a2Oracle NVL\u51fd\u6570\u7684\u591a&#46;&#46;&#46;<\/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-200001","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200001","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=200001"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200001\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200001"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200001"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200001"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}