<\/b> <\/p>\n\u4e86\u89e3Oracle\u7684NVL\u51fd\u6570\u53ca\u5176\u7528\u6cd5\uff0c\u5e76\u9644\u5e26\u793a\u4f8b<\/h1>\n
\u6570\u636e\u5e93\u5c0f\u767d\u4e00\u679a\uff0c\u6b63\u5728\u4e0d\u65ad\u5b66\u4e60\u79ef\u7d2f\u77e5\u8bc6\uff0c\u73b0\u5c06\u5b66\u4e60\u5230\u7684\u77e5\u8bc6\u8bb0\u5f55\u4e00\u4e0b\uff0c\u4e5f\u662f\u5c06\u6211\u7684\u6240\u5f97\u5206\u4eab\u7ed9\u5927\u5bb6\uff01\u800c\u4eca\u5929\u8fd9\u7bc7\u6587\u7ae0\u300a\u4e86\u89e3Oracle\u7684NVL\u51fd\u6570\u53ca\u5176\u7528\u6cd5\uff0c\u5e76\u9644\u5e26\u793a\u4f8b\u300b\u5e26\u5927\u5bb6\u6765\u4e86\u89e3\u4e00\u4e0b##content_title##\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u4ece\u800c\u5f25\u8865\u81ea\u5df1\u7684\u4e0d\u8db3\uff0c\u52a9\u529b\u5b9e\u6218\u5f00\u53d1\uff01<\/p>\n
<\/p>\n
Oracle NVL\u51fd\u6570\u8be6\u89e3\u53ca\u7528\u6cd5\u793a\u4f8b<\/p>\n
\u5728Oracle\u6570\u636e\u5e93\u4e2d\uff0cNVL\u51fd\u6570\u662f\u4e00\u79cd\u975e\u5e38\u5e38\u7528\u7684\u51fd\u6570\uff0c\u5176\u4f5c\u7528\u662f\u7528\u4e8e\u5224\u65ad\u4e00\u4e2a\u503c\u662f\u5426\u4e3anull\uff0c\u82e5\u4e3anull\u5219\u8fd4\u56de\u53e6\u4e00\u4e2a\u6307\u5b9a\u7684\u503c\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecdNVL\u51fd\u6570\u7684\u8bed\u6cd5\u3001\u7528\u6cd5\u53ca\u63d0\u4f9b\u4e00\u4e9b\u793a\u4f8b\u4ee3\u7801\u4ee5\u5e2e\u52a9\u8bfb\u8005\u66f4\u597d\u5730\u7406\u89e3\u548c\u5e94\u7528NVL\u51fd\u6570\u3002<\/p>\n
NVL\u51fd\u6570\u7684\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n
NVL(expr1, expr2)<\/pre>\n\u5176\u4e2d\uff0cexpr1\u662f\u8981\u5224\u65ad\u7684\u503c\uff0c\u5982\u679c\u4e3anull\u5219\u8fd4\u56deexpr2\uff0c\u5426\u5219\u8fd4\u56deexpr1\u3002<\/p>\n
2. NVL\u51fd\u6570\u7528\u6cd5\u793a\u4f8b<\/h2>\n
\u793a\u4f8b\u4e00\uff1a\u5c06null\u503c\u66ff\u6362\u4e3a\u6307\u5b9a\u503c<\/h3>\n
SELECT NVL(salary, 0) AS salary_new\nFROM employees;<\/pre>\n\u5728\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0c\u5982\u679cemployees\u8868\u4e2d\u7684salary\u5b57\u6bb5\u4e3anull\uff0cNVL\u51fd\u6570\u5c06\u5176\u66ff\u6362\u4e3a0\u3002<\/p>\n
\u793a\u4f8b\u4e8c\uff1a\u6761\u4ef6\u5224\u65ad<\/h3>\n
SELECT employee_name, NVL(salary, 0) AS salary\nFROM employees\nWHERE department = 'IT';<\/pre>\n\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0cNVL\u51fd\u6570\u7528\u4e8e\u5224\u65ad\u5458\u5de5\u7684\u5de5\u8d44\u662f\u5426\u4e3anull\uff0c\u5982\u679c\u662fnull\uff0c\u5219\u66ff\u6362\u4e3a0\u3002\u540c\u65f6\uff0c\u901a\u8fc7WHERE\u5b50\u53e5\u7b5b\u9009\u51fa\u90e8\u95e8\u4e3aIT\u7684\u5458\u5de5\u4fe1\u606f\u3002<\/p>\n
\u793a\u4f8b\u4e09\uff1a\u5d4c\u5957NVL\u51fd\u6570<\/h3>\n
SELECT NVL(NVL(salary, 0) + NVL(bonus, 0), 0) AS total_income\nFROM employees;<\/pre>\n\u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0cNVL\u51fd\u6570\u88ab\u5d4c\u5957\u4f7f\u7528\uff0c\u5148\u5224\u65adsalary\u548cbonus\u5b57\u6bb5\u662f\u5426\u4e3anull\uff0c\u7136\u540e\u8fdb\u884c\u52a0\u6cd5\u64cd\u4f5c\uff0c\u6700\u540e\u5c06\u7ed3\u679c\u66ff\u6362\u4e3a0\u3002<\/p>\n
3. \u603b\u7ed3<\/h2>\n
\u901a\u8fc7\u672c\u6587\u7684\u4ecb\u7ecd\uff0c\u8bfb\u8005\u5e94\u8be5\u5bf9Oracle\u6570\u636e\u5e93\u4e2d\u7684NVL\u51fd\u6570\u6709\u4e86\u66f4\u6df1\u5165\u7684\u4e86\u89e3\u3002NVL\u51fd\u6570\u5728\u5904\u7406null\u503c\u65f6\u975e\u5e38\u6709\u7528\uff0c\u80fd\u591f\u7b80\u6d01\u5730\u5b9e\u73b0\u5bf9\u5b57\u6bb5\u7684\u5224\u65ad\u548c\u66ff\u6362\u64cd\u4f5c\u3002\u8bfb\u8005\u53ef\u4ee5\u6839\u636e\u5177\u4f53\u4e1a\u52a1\u9700\u6c42\u7075\u6d3b\u8fd0\u7528NVL\u51fd\u6570\uff0c\u63d0\u9ad8SQL\u67e5\u8be2\u7684\u6548\u7387\u548c\u51c6\u786e\u6027\u3002<\/p>\n
\u5e0c\u671b\u672c\u6587\u5bf9\u8bfb\u8005\u6709\u6240\u5e2e\u52a9\uff0c\u8ba9\u5927\u5bb6\u5bf9NVL\u51fd\u6570\u6709\u66f4\u6e05\u6670\u7684\u8ba4\u8bc6\u548c\u8fd0\u7528\u3002\u611f\u8c22\u9605\u8bfb\uff01<\/p>\n
\u672c\u7bc7\u5173\u4e8e\u300a\u4e86\u89e3Oracle\u7684NVL\u51fd\u6570\u53ca\u5176\u7528\u6cd5\uff0c\u5e76\u9644\u5e26\u793a\u4f8b\u300b\u7684\u4ecb\u7ecd\u5c31\u5230\u6b64\u7ed3\u675f\u5566\uff0c\u4f46\u662f\u5b66\u65e0\u6b62\u5883\uff0c\u60f3\u8981\u4e86\u89e3\u5b66\u4e60\u66f4\u591a\u5173\u4e8e\u6570\u636e\u5e93\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u8bf7\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff01<\/p>\n
\n
- \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
\u4e86\u89e3Oracle\u7684NVL\u51fd\u6570\u53ca\u5176...<\/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-199972","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199972","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=199972"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199972\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199972"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199972"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199972"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}