{"id":162621,"date":"2024-11-04T16:37:21","date_gmt":"2024-11-04T08:37:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/162621\/"},"modified":"2024-11-04T16:37:22","modified_gmt":"2024-11-04T08:37:22","slug":"%e8%a6%8b%e5%be%ae%e7%9f%a5%e8%91%97%ef%bc%9a%e5%be%9eselect%e8%aa%9e%e5%8f%a5%e7%9c%8boracle%e6%9f%a5%e8%a9%a2%e5%8e%9f%e7%90%86","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/162621\/","title":{"rendered":"\u898b\u5fae\u77e5\u8457\uff1a\u5f9eSelect\u8a9e\u53e5\u770bOracle\u67e5\u8a62\u539f\u7406"},"content":{"rendered":"<h1 id=\"%e8%a6%8b%e5%be%ae%e7%9f%a5%e8%91%97%ef%bc%9a%e5%be%9eselect%e8%aa%9e%e5%8f%a5%e7%9c%8boracle%e6%9f%a5%e8%a9%a2%e5%8e%9f%e7%90%86-kuSXIipbmv\">\u898b\u5fae\u77e5\u8457\uff1a\u5f9eSelect\u8a9e\u53e5\u770bOracle\u67e5\u8a62\u539f\u7406<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u67e5\u8a62\u8a9e\u53e5\u662f\u7528\u6236\u8207\u6578\u64da\u5eab\u4ea4\u4e92\u7684\u4e3b\u8981\u65b9\u5f0f\u3002Oracle\u4f5c\u70ba\u4e00\u500b\u5f37\u5927\u7684\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u7cfb\u7d71\uff0c\u5176\u67e5\u8a62\u8a9e\u53e5\u7684\u8a2d\u8a08\u548c\u57f7\u884c\u539f\u7406\u5c0d\u65bc\u6578\u64da\u7684\u6aa2\u7d22\u548c\u8655\u7406\u81f3\u95dc\u91cd\u8981\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eOracle\u7684Select\u8a9e\u53e5\u53ca\u5176\u80cc\u5f8c\u7684\u67e5\u8a62\u539f\u7406\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u6578\u64da\u5eab\u7684\u904b\u4f5c\u3002<\/p>\n<h2 id=\"1-select%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%9f%ba%e6%9c%ac%e7%b5%90%e6%a7%8b-kuSXIipbmv\">1. Select\u8a9e\u53e5\u7684\u57fa\u672c\u7d50\u69cb<\/h2>\n<p>Oracle\u7684Select\u8a9e\u53e5\u901a\u5e38\u9075\u5faa\u4ee5\u4e0b\u57fa\u672c\u7d50\u69cb\uff1a<\/p>\n<pre><code>\nSELECT [\u5217\u540d1], [\u5217\u540d2], ...\nFROM [\u8868\u540d]\nWHERE [\u689d\u4ef6]\nORDER BY [\u6392\u5e8f\u5217]\n<\/code><\/pre>\n<p>\u9019\u88e1\uff0c<code>SELECT<\/code>\u7528\u65bc\u6307\u5b9a\u8981\u6aa2\u7d22\u7684\u5217\uff0c<code>FROM<\/code>\u6307\u5b9a\u6578\u64da\u4f86\u6e90\u7684\u8868\uff0c<code>WHERE<\/code>\u7528\u65bc\u904e\u6ffe\u6578\u64da\uff0c<code>ORDER BY<\/code>\u5247\u7528\u65bc\u6392\u5e8f\u7d50\u679c\u3002<\/p>\n<h2 id=\"2-%e6%9f%a5%e8%a9%a2%e5%9f%b7%e8%a1%8c%e7%9a%84%e9%81%8e%e7%a8%8b-kuSXIipbmv\">2. \u67e5\u8a62\u57f7\u884c\u7684\u904e\u7a0b<\/h2>\n<p>\u7576\u7528\u6236\u57f7\u884c\u4e00\u500bSelect\u8a9e\u53e5\u6642\uff0cOracle\u6703\u7d93\u6b77\u4e00\u7cfb\u5217\u7684\u6b65\u9a5f\u4f86\u8655\u7406\u8a72\u67e5\u8a62\uff1a<\/p>\n<ul>\n<li><strong>\u89e3\u6790\uff08Parsing\uff09<\/strong>\uff1aOracle\u9996\u5148\u6703\u89e3\u6790SQL\u8a9e\u53e5\uff0c\u6aa2\u67e5\u8a9e\u6cd5\u7684\u6b63\u78ba\u6027\uff0c\u4e26\u751f\u6210\u4e00\u500b\u57f7\u884c\u8a08\u5283\u3002<\/li>\n<li><strong>\u512a\u5316\uff08Optimization\uff09<\/strong>\uff1a\u5728\u751f\u6210\u57f7\u884c\u8a08\u5283\u5f8c\uff0cOracle\u6703\u9078\u64c7\u6700\u4f73\u7684\u57f7\u884c\u8def\u5f91\uff0c\u9019\u53ef\u80fd\u6d89\u53ca\u5230\u4f7f\u7528\u7d22\u5f15\u3001\u9078\u64c7\u4e0d\u540c\u7684\u9023\u63a5\u65b9\u6cd5\u7b49\u3002<\/li>\n<li><strong>\u57f7\u884c\uff08Execution\uff09<\/strong>\uff1a\u6839\u64da\u512a\u5316\u5f8c\u7684\u57f7\u884c\u8a08\u5283\uff0cOracle\u6703\u5be6\u969b\u57f7\u884c\u67e5\u8a62\uff0c\u5f9e\u6578\u64da\u5eab\u4e2d\u6aa2\u7d22\u6240\u9700\u7684\u6578\u64da\u3002<\/li>\n<li><strong>\u8fd4\u56de\u7d50\u679c\uff08Result Return\uff09<\/strong>\uff1a\u6700\u5f8c\uff0c\u67e5\u8a62\u7d50\u679c\u6703\u8fd4\u56de\u7d66\u7528\u6236\u3002<\/li>\n<\/ul>\n<h2 id=\"3-%e6%9f%a5%e8%a9%a2%e5%84%aa%e5%8c%96%e7%9a%84%e6%8a%80%e5%b7%a7-kuSXIipbmv\">3. \u67e5\u8a62\u512a\u5316\u7684\u6280\u5de7<\/h2>\n<p>\u70ba\u4e86\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u63a1\u53d6\u4ee5\u4e0b\u5e7e\u7a2e\u512a\u5316\u6280\u5de7\uff1a<\/p>\n<ul>\n<li><strong>\u4f7f\u7528\u7d22\u5f15<\/strong>\uff1a\u7d22\u5f15\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u901f\u5ea6\uff0c\u7279\u5225\u662f\u5728\u5927\u6578\u64da\u96c6\u4e0a\u3002\u4f7f\u7528<code>CREATE INDEX<\/code>\u8a9e\u53e5\u4f86\u5275\u5efa\u7d22\u5f15\u3002<\/li>\n<li><strong>\u907f\u514dSELECT *<\/strong>\uff1a\u9078\u64c7\u5177\u9ad4\u7684\u5217\u800c\u4e0d\u662f\u4f7f\u7528<code>*<\/code>\uff0c\u53ef\u4ee5\u6e1b\u5c11\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u50b3\u8f38\u3002<\/li>\n<li><strong>\u4f7f\u7528WHERE\u5b50\u53e5<\/strong>\uff1a\u901a\u904e\u904e\u6ffe\u4e0d\u5fc5\u8981\u7684\u6578\u64da\u4f86\u6e1b\u5c11\u67e5\u8a62\u7684\u8ca0\u64d4\u3002<\/li>\n<li><strong>\u5206\u6790\u57f7\u884c\u8a08\u5283<\/strong>\uff1a\u4f7f\u7528<code>EXPLAIN PLAN<\/code>\u4f86\u67e5\u770b\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\uff0c\u5f9e\u800c\u627e\u51fa\u6f5b\u5728\u7684\u6027\u80fd\u74f6\u9838\u3002<\/li>\n<\/ul>\n<h2 id=\"4-%e5%af%a6%e4%be%8b%e5%88%86%e6%9e%90-kuSXIipbmv\">4. \u5be6\u4f8b\u5206\u6790<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u67e5\u8a62\u793a\u4f8b\uff1a<\/p>\n<pre><code>\nSELECT employee_id, first_name, last_name\nFROM employees\nWHERE department_id = 10\nORDER BY last_name;\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6211\u5011\u5f9e<code>employees<\/code>\u8868\u4e2d\u9078\u64c7\u4e86\u54e1\u5de5\u7684ID\u548c\u59d3\u540d\uff0c\u4e26\u4e14\u53ea\u6aa2\u7d22\u90e8\u9580ID\u70ba10\u7684\u54e1\u5de5\uff0c\u6700\u5f8c\u6309\u59d3\u6c0f\u6392\u5e8f\u3002\u9019\u6a23\u7684\u67e5\u8a62\u80fd\u5920\u6709\u6548\u5730\u904e\u6ffe\u6578\u64da\uff0c\u4e26\u4e14\u901a\u904e\u7d22\u5f15\u52a0\u901f\u67e5\u8a62\u904e\u7a0b\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-kuSXIipbmv\">\u7e3d\u7d50<\/h2>\n<p>Oracle\u7684Select\u8a9e\u53e5\u662f\u6578\u64da\u6aa2\u7d22\u7684\u6838\u5fc3\uff0c\u7406\u89e3\u5176\u67e5\u8a62\u539f\u7406\u5c0d\u65bc\u6578\u64da\u5eab\u7684\u9ad8\u6548\u4f7f\u7528\u81f3\u95dc\u91cd\u8981\u3002\u901a\u904e\u5408\u7406\u7684\u67e5\u8a62\u7d50\u69cb\u548c\u512a\u5316\u6280\u5de7\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\uff0c\u5f9e\u800c\u63d0\u5347\u6574\u9ad4\u7cfb\u7d71\u7684\u6548\u7387\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\u4f86\u8aaa\uff0c\u9078\u64c7\u5408\u9069\u7684<code><a href=\"https:\/\/server.hk\">VPS<\/a><\/code>\u6216<code><a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a><\/code>\u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u4e00\u500b\u91cd\u8981\u7684\u8003\u91cf\uff0c\u9019\u5c07\u6709\u52a9\u65bc\u652f\u6301\u5176\u6578\u64da\u5eab\u7684\u7a69\u5b9a\u904b\u884c\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22Oracle\u67e5\u8a62\u539f\u7406\uff0c\u900f\u904eSelect\u8a9e\u53e5\u6df1\u5165\u7406\u89e3\u898b\u5fae\u77e5\u8457\u7684\u667a\u6167\uff0c\u63ed\u793a\u6578\u64da\u6aa2\u7d22\u7684\u6838\u5fc3\u6a5f\u5236\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-162621","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162621","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=162621"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162621\/revisions"}],"predecessor-version":[{"id":162622,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/162621\/revisions\/162622"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=162621"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=162621"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=162621"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}