{"id":160299,"date":"2024-11-03T21:56:17","date_gmt":"2024-11-03T13:56:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/160299\/"},"modified":"2024-11-03T21:56:18","modified_gmt":"2024-11-03T13:56:18","slug":"oceanbase-%e6%95%99%e7%a8%8b%ef%bc%9aoceanbase-%e6%af%94%e8%bc%83%e6%a2%9d%e4%bb%b6%e4%b8%ad%e7%9a%84%e7%a9%ba%e5%80%bc","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/160299\/","title":{"rendered":"OceanBase \u6559\u7a0b\uff1aOceanBase \u6bd4\u8f03\u689d\u4ef6\u4e2d\u7684\u7a7a\u503c"},"content":{"rendered":"

OceanBase \u6559\u7a0b\uff1aOceanBase \u6bd4\u8f03\u689d\u4ef6\u4e2d\u7684\u7a7a\u503c<\/h1>\n

\u5728\u7576\u4eca\u7684\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cOceanBase \u4f5c\u70ba\u4e00\u500b\u9ad8\u6027\u80fd\u7684\u5206\u4f48\u5f0f\u6578\u64da\u5eab\uff0c\u8d8a\u4f86\u8d8a\u53d7\u5230\u958b\u767c\u8005\u548c\u4f01\u696d\u7684\u9752\u775e\u3002\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u548c\u9ad8\u4f75\u767c\u8acb\u6c42\u7684\u5834\u666f\u4e0b\uff0cOceanBase \u7684\u512a\u52e2\u986f\u800c\u6613\u898b\u3002\u7136\u800c\uff0c\u5728\u4f7f\u7528 OceanBase \u9032\u884c\u6578\u64da\u67e5\u8a62\u6642\uff0c\u5982\u4f55\u6b63\u78ba\u8655\u7406\u7a7a\u503c\uff08NULL\uff09\u662f\u4e00\u500b\u91cd\u8981\u7684\u8ab2\u984c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e OceanBase \u4e2d\u7a7a\u503c\u7684\u6bd4\u8f03\u689d\u4ef6\u53ca\u5176\u4f7f\u7528\u65b9\u6cd5\u3002<\/p>\n

\u4ec0\u9ebc\u662f\u7a7a\u503c\uff08NULL\uff09\uff1f<\/h2>\n

\u5728\u6578\u64da\u5eab\u4e2d\uff0c\u7a7a\u503c\uff08NULL\uff09\u8868\u793a\u4e00\u500b\u7f3a\u5931\u7684\u6216\u672a\u77e5\u7684\u6578\u64da\u3002\u5b83\u8207\u96f6\uff080\uff09\u6216\u7a7a\u5b57\u7b26\u4e32\uff08””\uff09\u4e0d\u540c\uff0c\u56e0\u70ba\u9019\u4e9b\u503c\u662f\u5177\u9ad4\u7684\uff0c\u800c\u7a7a\u503c\u5247\u8868\u793a\u201c\u7121\u503c\u201d\u3002\u5728 OceanBase \u4e2d\uff0c\u6b63\u78ba\u8655\u7406\u7a7a\u503c\u5c0d\u65bc\u78ba\u4fdd\u67e5\u8a62\u7d50\u679c\u7684\u6e96\u78ba\u6027\u81f3\u95dc\u91cd\u8981\u3002<\/p>\n

\u7a7a\u503c\u7684\u6bd4\u8f03\u689d\u4ef6<\/h2>\n

\u5728 SQL \u67e5\u8a62\u4e2d\uff0c\u7a7a\u503c\u7684\u6bd4\u8f03\u689d\u4ef6\u8207\u5176\u4ed6\u6578\u64da\u985e\u578b\u6709\u6240\u4e0d\u540c\u3002\u6839\u64da SQL \u6a19\u6e96\uff0c\u4efb\u4f55\u8207 NULL \u7684\u6bd4\u8f03\u90fd\u6703\u8fd4\u56de NULL\uff0c\u800c\u4e0d\u662f TRUE \u6216 FALSE\u3002\u9019\u610f\u5473\u8457\uff0c\u5982\u679c\u4f60\u5617\u8a66\u4f7f\u7528\u7b49\u65bc\uff08=\uff09\u6216\u4e0d\u7b49\u65bc\uff08\uff09\u904b\u7b97\u7b26\u4f86\u6bd4\u8f03\u7a7a\u503c\uff0c\u7d50\u679c\u5c07\u4e0d\u6703\u5982\u9810\u671f\u90a3\u6a23\u8fd4\u56de\u5e03\u723e\u503c\u3002<\/p>\n

\u4f7f\u7528 IS NULL \u548c IS NOT NULL<\/h3>\n

\u5728 OceanBase \u4e2d\uff0c\u8655\u7406\u7a7a\u503c\u7684\u4e3b\u8981\u65b9\u6cd5\u662f\u4f7f\u7528 IS NULL<\/code> \u548c IS NOT NULL<\/code> \u689d\u4ef6\u3002\u9019\u4e9b\u689d\u4ef6\u53ef\u4ee5\u7528\u65bc\u67e5\u8a62\u4e2d\uff0c\u4ee5\u7be9\u9078\u51fa\u5305\u542b\u6216\u4e0d\u5305\u542b\u7a7a\u503c\u7684\u8a18\u9304\u3002<\/p>\n

SELECT * FROM users WHERE email IS NULL;<\/code><\/pre>\n
\u4e0a\u8ff0\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u70ba\u7a7a\u7684\u7528\u6236\u3002<\/p>\n
SELECT * FROM users WHERE email IS NOT NULL;<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5247\u6703\u8fd4\u56de\u6240\u6709\u64c1\u6709\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u7684\u7528\u6236\u3002<\/p>\n
\u7a7a\u503c\u5728\u6392\u5e8f\u4e2d\u7684\u5f71\u97ff<\/h3>\n
\u5728\u9032\u884c\u6392\u5e8f\u6642\uff0c\u7a7a\u503c\u7684\u8655\u7406\u4e5f\u9700\u8981\u7279\u5225\u6ce8\u610f\u3002\u5728 OceanBase \u4e2d\uff0c\u7a7a\u503c\u901a\u5e38\u6703\u88ab\u8996\u70ba\u6700\u5c0f\u503c\uff0c\u9019\u610f\u5473\u8457\u5728\u5347\u5e8f\u6392\u5e8f\u6642\uff0c\u7a7a\u503c\u6703\u6392\u5728\u6700\u524d\u9762\uff0c\u800c\u5728\u964d\u5e8f\u6392\u5e8f\u6642\uff0c\u7a7a\u503c\u5247\u6703\u6392\u5728\u6700\u5f8c\u9762\u3002<\/p>\n
SELECT * FROM users ORDER BY email ASC;<\/code><\/pre>\n
\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6240\u6709\u96fb\u5b50\u90f5\u4ef6\u70ba\u7a7a\u7684\u7528\u6236\u5c07\u6703\u6392\u5728\u7d50\u679c\u7684\u6700\u4e0a\u65b9\u3002<\/p>\n
\u7a7a\u503c\u7684\u805a\u5408\u51fd\u6578<\/h2>\n
\u5728\u4f7f\u7528\u805a\u5408\u51fd\u6578\uff08\u5982 COUNT<\/code>\u3001SUM<\/code>\u3001AVG<\/code> \u7b49\uff09\u6642\uff0c\u7a7a\u503c\u7684\u5b58\u5728\u4e5f\u6703\u5f71\u97ff\u7d50\u679c\u3002\u4f8b\u5982\uff0cCOUNT<\/code> \u51fd\u6578\u4e0d\u6703\u8a08\u7b97\u7a7a\u503c\uff0c\u800c SUM<\/code> \u548c AVG<\/code> \u51fd\u6578\u5247\u6703\u5ffd\u7565\u7a7a\u503c\u3002<\/p>\n
SELECT COUNT(email) FROM users;<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u64c1\u6709\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u7684\u7528\u6236\u6578\u91cf\uff0c\u7a7a\u503c\u4e0d\u6703\u88ab\u8a08\u7b97\u5728\u5167\u3002<\/p>\n
\u7d50\u8ad6<\/h2>\n
\u5728 OceanBase \u4e2d\uff0c\u6b63\u78ba\u8655\u7406\u7a7a\u503c\u662f\u78ba\u4fdd\u6578\u64da\u67e5\u8a62\u6e96\u78ba\u6027\u7684\u91cd\u8981\u6b65\u9a5f\u3002\u901a\u904e\u4f7f\u7528 IS NULL<\/code> \u548c IS NOT NULL<\/code> \u4f86\u7be9\u9078\u6578\u64da\uff0c\u4e26\u7406\u89e3\u7a7a\u503c\u5728\u6392\u5e8f\u548c\u805a\u5408\u51fd\u6578\u4e2d\u7684\u5f71\u97ff\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u66f4\u6709\u6548\u5730\u7ba1\u7406\u548c\u67e5\u8a62\u6578\u64da\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 \u9999\u6e2fVPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4f86\u904b\u884c\u60a8\u7684 OceanBase \u6578\u64da\u5eab\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u9700\u6c42\u3002\u7121\u8ad6\u662f\u5c0f\u578b\u9805\u76ee\u9084\u662f\u5927\u578b\u4f01\u696d\u61c9\u7528\uff0c\u6211\u5011\u7684 \u4f3a\u670d\u5668<\/a> \u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u7a69\u5b9a\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5b78\u7fd2\u5982\u4f55\u5728 OceanBase \u4e2d\u6bd4\u8f03\u689d\u4ef6\u4e2d\u7684\u7a7a\u503c\uff0c\u638c\u63e1\u6578\u64da\u67e5\u8a62\u6280\u5de7\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u6548\u7387\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-160299","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160299","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=160299"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160299\/revisions"}],"predecessor-version":[{"id":160300,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160299\/revisions\/160300"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=160299"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=160299"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=160299"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}