{"id":94640,"date":"2024-10-19T19:56:21","date_gmt":"2024-10-19T11:56:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/94640\/"},"modified":"2024-10-19T19:56:22","modified_gmt":"2024-10-19T11:56:22","slug":"oracle-%e6%9c%89%e8%b6%a3%e6%8e%92%e5%ba%8f%e5%8c%85%e6%8b%ac%e9%82%a3%e4%ba%9b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/94640\/","title":{"rendered":"Oracle \u6709\u8da3\u6392\u5e8f\u5305\u62ec\u90a3\u4e9b"},"content":{"rendered":"

Oracle \u6709\u8da3\u6392\u5e8f\u5305\u62ec\u90a3\u4e9b<\/h1>\n

\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u6392\u5e8f\u662f\u4e00\u500b\u975e\u5e38\u91cd\u8981\u7684\u64cd\u4f5c\uff0c\u5c24\u5176\u662f\u5728\u8655\u7406\u5927\u91cf\u6578\u64da\u6642\u3002Oracle \u4f5c\u70ba\u4e00\u500b\u5f37\u5927\u7684\u8cc7\u6599\u5eab\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u6392\u5e8f\u65b9\u6cd5\uff0c\u8b93\u7528\u6236\u80fd\u5920\u6839\u64da\u4e0d\u540c\u7684\u9700\u6c42\u9032\u884c\u6578\u64da\u7684\u6392\u5e8f\u3002\u672c\u6587\u5c07\u63a2\u8a0e Oracle \u4e2d\u4e00\u4e9b\u6709\u8da3\u7684\u6392\u5e8f\u65b9\u6cd5\u53ca\u5176\u61c9\u7528\u3002<\/p>\n

1. \u57fa\u672c\u6392\u5e8f<\/h2>\n

\u5728 Oracle \u4e2d\uff0c\u6700\u57fa\u672c\u7684\u6392\u5e8f\u65b9\u6cd5\u662f\u4f7f\u7528 ORDER BY<\/code> \u5b50\u53e5\u3002\u9019\u500b\u5b50\u53e5\u53ef\u4ee5\u7528\u4f86\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u5347\u5e8f\u6216\u964d\u5e8f\u6392\u5e8f\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u4f8b\u5b50\uff1a<\/p>\n

SELECT * FROM employees\nORDER BY last_name ASC;<\/code><\/pre>\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u67e5\u8a62\u7d50\u679c\u5c07\u6839\u64da\u54e1\u5de5\u7684\u59d3\u6c0f\u9032\u884c\u5347\u5e8f\u6392\u5e8f\u3002<\/p>\n
2. \u591a\u5217\u6392\u5e8f<\/h2>\n
\u9664\u4e86\u55ae\u4e00\u5217\u7684\u6392\u5e8f\uff0cOracle \u4e5f\u652f\u6301\u591a\u5217\u6392\u5e8f\u3002\u9019\u610f\u5473\u8457\u7528\u6236\u53ef\u4ee5\u6839\u64da\u591a\u500b\u5217\u7684\u503c\u9032\u884c\u6392\u5e8f\uff0c\u9019\u5728\u8655\u7406\u8907\u96dc\u6578\u64da\u6642\u975e\u5e38\u6709\u7528\u3002\u4ee5\u4e0b\u662f\u591a\u5217\u6392\u5e8f\u7684\u7bc4\u4f8b\uff1a<\/p>\n
SELECT * FROM employees\nORDER BY department_id ASC, last_name DESC;<\/code><\/pre>\n
\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u9996\u5148\u6839\u64da\u90e8\u9580 ID \u9032\u884c\u5347\u5e8f\u6392\u5e8f\uff0c\u7136\u5f8c\u5728\u6bcf\u500b\u90e8\u9580\u5167\u6839\u64da\u59d3\u6c0f\u9032\u884c\u964d\u5e8f\u6392\u5e8f\u3002<\/p>\n
3. \u81ea\u5b9a\u7fa9\u6392\u5e8f<\/h2>\n
Oracle \u5141\u8a31\u7528\u6236\u4f7f\u7528 CASE<\/code> \u8a9e\u53e5\u4f86\u9032\u884c\u81ea\u5b9a\u7fa9\u6392\u5e8f\u3002\u9019\u5c0d\u65bc\u9700\u8981\u7279\u5b9a\u6392\u5e8f\u908f\u8f2f\u7684\u60c5\u6cc1\u975e\u5e38\u6709\u7528\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
SELECT * FROM employees\nORDER BY CASE \n             WHEN job_title = 'Manager' THEN 1\n             WHEN job_title = 'Developer' THEN 2\n             ELSE 3\n         END;<\/code><\/pre>\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6240\u6709\u7684\u7d93\u7406\u5c07\u6392\u5728\u6700\u524d\u9762\uff0c\u7136\u5f8c\u662f\u958b\u767c\u4eba\u54e1\uff0c\u5176\u4ed6\u8077\u4f4d\u5247\u6392\u5728\u6700\u5f8c\u3002<\/p>\n
4. \u96a8\u6a5f\u6392\u5e8f<\/h2>\n
\u6709\u6642\u5019\uff0c\u7528\u6236\u53ef\u80fd\u5e0c\u671b\u96a8\u6a5f\u6392\u5e8f\u67e5\u8a62\u7d50\u679c\u3002Oracle \u63d0\u4f9b\u4e86 DBMS_RANDOM.VALUE<\/code> \u51fd\u6578\u4f86\u5be6\u73fe\u9019\u4e00\u9ede\u3002\u4ee5\u4e0b\u662f\u96a8\u6a5f\u6392\u5e8f\u7684\u7bc4\u4f8b\uff1a<\/p>\n
SELECT * FROM employees\nORDER BY DBMS_RANDOM.VALUE;<\/code><\/pre>\n
\u9019\u6a23\u7684\u67e5\u8a62\u5c07\u8fd4\u56de\u96a8\u6a5f\u6392\u5e8f\u7684\u54e1\u5de5\u5217\u8868\uff0c\u9019\u5728\u67d0\u4e9b\u61c9\u7528\u5834\u666f\u4e2d\u53ef\u80fd\u6703\u975e\u5e38\u6709\u7528\u3002<\/p>\n
5. \u6392\u5e8f\u8207\u5206\u7d44<\/h2>\n
\u5728\u9032\u884c\u5206\u7d44\u64cd\u4f5c\u6642\uff0c\u6392\u5e8f\u4e5f\u53ef\u4ee5\u8207 GROUP BY<\/code> \u5b50\u53e5\u7d50\u5408\u4f7f\u7528\u3002\u9019\u6a23\u53ef\u4ee5\u5728\u5206\u7d44\u5f8c\u5c0d\u7d50\u679c\u9032\u884c\u6392\u5e8f\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
SELECT department_id, COUNT(*) AS employee_count\nFROM employees\nGROUP BY department_id\nORDER BY employee_count DESC;<\/code><\/pre>\n
\u9019\u500b\u67e5\u8a62\u5c07\u6839\u64da\u6bcf\u500b\u90e8\u9580\u7684\u54e1\u5de5\u6578\u91cf\u9032\u884c\u964d\u5e8f\u6392\u5e8f\uff0c\u986f\u793a\u51fa\u54e1\u5de5\u6578\u91cf\u6700\u591a\u7684\u90e8\u9580\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
Oracle \u63d0\u4f9b\u4e86\u591a\u7a2e\u9748\u6d3b\u7684\u6392\u5e8f\u65b9\u6cd5\uff0c\u5f9e\u57fa\u672c\u7684\u5347\u5e8f\u548c\u964d\u5e8f\u6392\u5e8f\u5230\u66f4\u8907\u96dc\u7684\u81ea\u5b9a\u7fa9\u548c\u96a8\u6a5f\u6392\u5e8f\uff0c\u9019\u4e9b\u529f\u80fd\u4f7f\u5f97\u7528\u6236\u80fd\u5920\u6839\u64da\u4e0d\u540c\u7684\u9700\u6c42\u9032\u884c\u6578\u64da\u7684\u6709\u6548\u7ba1\u7406\u3002\u7121\u8ad6\u662f\u8655\u7406\u7c21\u55ae\u7684\u67e5\u8a62\u9084\u662f\u8907\u96dc\u7684\u6578\u64da\u5206\u6790\uff0c\u4e86\u89e3\u9019\u4e9b\u6392\u5e8f\u65b9\u6cd5\u90fd\u80fd\u5e6b\u52a9\u7528\u6236\u66f4\u597d\u5730\u5229\u7528 Oracle \u8cc7\u6599\u5eab\u7684\u5f37\u5927\u529f\u80fd\u3002<\/p>\n
\u5982\u679c\u60a8\u5c0d\u65bc \u9999\u6e2fVPS<\/a> \u670d\u52d9\u6709\u8208\u8da3\uff0c\u6216\u60f3\u4e86\u89e3\u66f4\u591a\u95dc\u65bc \u4e91\u670d\u52a1\u5668<\/a> \u7684\u8cc7\u8a0a\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22 Oracle \u6709\u8da3\u6392\u5e8f\u7684\u591a\u6837\u6027\uff0c\u5305\u62ec\u968f\u673a\u6392\u5e8f\u3001\u81ea\u7136\u6392\u5e8f\u548c\u81ea\u5b9a\u4e49\u6392\u5e8f\uff0c\u63d0\u5347\u6570\u636e\u5904\u7406\u7684\u7075\u6d3b\u6027\u4e0e\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-94640","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/94640","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=94640"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/94640\/revisions"}],"predecessor-version":[{"id":94641,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/94640\/revisions\/94641"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=94640"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=94640"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=94640"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}