{"id":186598,"date":"2024-11-11T07:15:20","date_gmt":"2024-11-10T23:15:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/186598\/"},"modified":"2024-11-11T07:15:22","modified_gmt":"2024-11-10T23:15:22","slug":"%e6%95%b8%e6%93%9a%e5%ba%ab%e9%97%9c%e4%bf%82%e9%81%8b%e7%ae%97%e4%b8%ad%e7%9a%84%e9%81%8b%e7%ae%97%e7%ac%a6%e8%99%9f%e6%a6%82%e8%bf%b0-%e6%95%b8%e6%93%9a%e5%ba%ab%e9%97%9c%e4%bf%82%e9%81%8b%e7%ae%97","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/186598\/","title":{"rendered":"\u6578\u64da\u5eab\u95dc\u4fc2\u904b\u7b97\u4e2d\u7684\u904b\u7b97\u7b26\u865f\u6982\u8ff0 (\u6578\u64da\u5eab\u95dc\u4fc2\u904b\u7b97\u4e2d\u95dc\u4fc2\u904b\u7b97\u7b26\u865f)"},"content":{"rendered":"<h1 id=\"%e6%95%b8%e6%93%9a%e5%ba%ab%e9%97%9c%e4%bf%82%e9%81%8b%e7%ae%97%e4%b8%ad%e7%9a%84%e9%81%8b%e7%ae%97%e7%ac%a6%e8%99%9f%e6%a6%82%e8%bf%b0-jwBkmjSxkY\">\u6578\u64da\u5eab\u95dc\u4fc2\u904b\u7b97\u4e2d\u7684\u904b\u7b97\u7b26\u865f\u6982\u8ff0<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0c\u95dc\u4fc2\u904b\u7b97\u662f\u8655\u7406\u6578\u64da\u7684\u6838\u5fc3\u3002\u95dc\u4fc2\u904b\u7b97\u7b26\u865f\u662f\u7528\u4f86\u57f7\u884c\u5404\u7a2e\u64cd\u4f5c\u7684\u5de5\u5177\uff0c\u9019\u4e9b\u64cd\u4f5c\u5305\u62ec\u67e5\u8a62\u3001\u66f4\u65b0\u3001\u522a\u9664\u548c\u63d2\u5165\u6578\u64da\u3002\u672c\u6587\u5c07\u5c0d\u6578\u64da\u5eab\u95dc\u4fc2\u904b\u7b97\u4e2d\u7684\u4e3b\u8981\u904b\u7b97\u7b26\u865f\u9032\u884c\u6982\u8ff0\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u5176\u529f\u80fd\u548c\u61c9\u7528\u3002<\/p>\n<h2 id=\"%e9%97%9c%e4%bf%82%e9%81%8b%e7%ae%97%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-jwBkmjSxkY\">\u95dc\u4fc2\u904b\u7b97\u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u95dc\u4fc2\u904b\u7b97\u662f\u57fa\u65bc\u6578\u5b78\u96c6\u5408\u8ad6\u7684\u6982\u5ff5\uff0c\u4e3b\u8981\u7528\u65bc\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u4e2d\u3002\u95dc\u4fc2\u578b\u6578\u64da\u5eab\u4e2d\u7684\u6578\u64da\u4ee5\u8868\u683c\u7684\u5f62\u5f0f\u5b58\u5132\uff0c\u6bcf\u500b\u8868\u683c\u7531\u884c\u548c\u5217\u7d44\u6210\u3002\u884c\u4ee3\u8868\u8a18\u9304\uff0c\u5217\u4ee3\u8868\u5c6c\u6027\u3002\u95dc\u4fc2\u904b\u7b97\u7b26\u865f\u5247\u7528\u65bc\u64cd\u4f5c\u9019\u4e9b\u8868\u683c\u4e2d\u7684\u6578\u64da\u3002<\/p>\n<h2 id=\"%e4%b8%bb%e8%a6%81%e7%9a%84%e9%97%9c%e4%bf%82%e9%81%8b%e7%ae%97%e7%ac%a6%e8%99%9f-jwBkmjSxkY\">\u4e3b\u8981\u7684\u95dc\u4fc2\u904b\u7b97\u7b26\u865f<\/h2>\n<h3 id=\"1-%e9%81%b8%e6%93%87%e9%81%8b%e7%ae%97%e7%ac%a6-%cf%83-jwBkmjSxkY\">1. \u9078\u64c7\u904b\u7b97\u7b26 (\u03c3)<\/h3>\n<p>\u9078\u64c7\u904b\u7b97\u7b26\u7528\u65bc\u5f9e\u95dc\u4fc2\u4e2d\u9078\u64c7\u6eff\u8db3\u7279\u5b9a\u689d\u4ef6\u7684\u884c\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>\u03c3<sub>\u689d\u4ef6<\/sub>(\u95dc\u4fc2)<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u82e5\u6709\u4e00\u500b\u540d\u70ba\u300c\u5b78\u751f\u300d\u7684\u8868\u683c\uff0c\u60f3\u8981\u9078\u64c7\u5e74\u9f61\u5927\u65bc18\u6b72\u7684\u5b78\u751f\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT * FROM \u5b78\u751f WHERE \u5e74\u9f61 &gt; 18;<\/code><\/pre>\n<h3 id=\"2-%e6%8a%95%e5%bd%b1%e9%81%8b%e7%ae%97%e7%ac%a6-%cf%80-jwBkmjSxkY\">2. \u6295\u5f71\u904b\u7b97\u7b26 (\u03c0)<\/h3>\n<p>\u6295\u5f71\u904b\u7b97\u7b26\u7528\u65bc\u5f9e\u95dc\u4fc2\u4e2d\u9078\u64c7\u7279\u5b9a\u7684\u5217\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>\u03c0<sub>\u5217\u540d<\/sub>(\u95dc\u4fc2)<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u82e5\u60f3\u8981\u5f9e\u300c\u5b78\u751f\u300d\u8868\u683c\u4e2d\u9078\u64c7\u5b78\u751f\u7684\u59d3\u540d\u548c\u5e74\u9f61\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT \u59d3\u540d, \u5e74\u9f61 FROM \u5b78\u751f;<\/code><\/pre>\n<h3 id=\"3-%e8%81%af%e6%8e%a5%e9%81%8b%e7%ae%97%e7%ac%a6-%e2%a8%9d-jwBkmjSxkY\">3. \u806f\u63a5\u904b\u7b97\u7b26 (\u2a1d)<\/h3>\n<p>\u806f\u63a5\u904b\u7b97\u7b26\u7528\u65bc\u5c07\u5169\u500b\u6216\u591a\u500b\u95dc\u4fc2\u6839\u64da\u5171\u540c\u7684\u5c6c\u6027\u9032\u884c\u5408\u4f75\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>\u95dc\u4fc21 \u2a1d \u95dc\u4fc22<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u82e5\u6709\u4e00\u500b\u300c\u5b78\u751f\u300d\u8868\u683c\u548c\u4e00\u500b\u300c\u8ab2\u7a0b\u300d\u8868\u683c\uff0c\u60f3\u8981\u67e5\u8a62\u6bcf\u4f4d\u5b78\u751f\u6240\u9078\u7684\u8ab2\u7a0b\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT \u5b78\u751f.\u59d3\u540d, \u8ab2\u7a0b.\u8ab2\u7a0b\u540d\u7a31 \nFROM \u5b78\u751f \nJOIN \u8ab2\u7a0b ON \u5b78\u751f.\u8ab2\u7a0bID = \u8ab2\u7a0b.ID;<\/code><\/pre>\n<h3 id=\"4-%e4%ba%a4%e9%9b%86%e9%81%8b%e7%ae%97%e7%ac%a6-%e2%88%a9-jwBkmjSxkY\">4. \u4ea4\u96c6\u904b\u7b97\u7b26 (\u2229)<\/h3>\n<p>\u4ea4\u96c6\u904b\u7b97\u7b26\u7528\u65bc\u7372\u53d6\u5169\u500b\u95dc\u4fc2\u4e2d\u5171\u540c\u7684\u884c\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>\u95dc\u4fc21 \u2229 \u95dc\u4fc22<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u82e5\u6709\u5169\u500b\u8868\u683c\u300c\u5b78\u751fA\u300d\u548c\u300c\u5b78\u751fB\u300d\uff0c\u60f3\u8981\u67e5\u8a62\u540c\u6642\u5728\u5169\u500b\u8868\u683c\u4e2d\u7684\u5b78\u751f\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT * FROM \u5b78\u751fA \nINTERSECT \nSELECT * FROM \u5b78\u751fB;<\/code><\/pre>\n<h3 id=\"5-%e8%81%af%e5%90%88%e9%81%8b%e7%ae%97%e7%ac%a6-%e2%88%aa-jwBkmjSxkY\">5. \u806f\u5408\u904b\u7b97\u7b26 (\u222a)<\/h3>\n<p>\u806f\u5408\u904b\u7b97\u7b26\u7528\u65bc\u7372\u53d6\u5169\u500b\u95dc\u4fc2\u7684\u6240\u6709\u884c\uff0c\u4e26\u53bb\u9664\u91cd\u8907\u7684\u884c\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>\u95dc\u4fc21 \u222a \u95dc\u4fc22<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u82e5\u60f3\u8981\u67e5\u8a62\u6240\u6709\u5b78\u751f\u7684\u59d3\u540d\uff0c\u4e0d\u8ad6\u4ed6\u5011\u4f86\u81ea\u54ea\u500b\u73ed\u7d1a\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT \u59d3\u540d FROM \u5b78\u751fA \nUNION \nSELECT \u59d3\u540d FROM \u5b78\u751fB;<\/code><\/pre>\n<h3 id=\"6-%e5%b7%ae%e9%9b%86%e9%81%8b%e7%ae%97%e7%ac%a6-%e2%88%92-jwBkmjSxkY\">6. \u5dee\u96c6\u904b\u7b97\u7b26 (\u2212)<\/h3>\n<p>\u5dee\u96c6\u904b\u7b97\u7b26\u7528\u65bc\u7372\u53d6\u5728\u4e00\u500b\u95dc\u4fc2\u4e2d\u4f46\u4e0d\u5728\u53e6\u4e00\u500b\u95dc\u4fc2\u4e2d\u7684\u884c\u3002\u5176\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>\u95dc\u4fc21 \u2212 \u95dc\u4fc22<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u82e5\u60f3\u8981\u67e5\u8a62\u5728\u300c\u5b78\u751fA\u300d\u4e2d\u4f46\u4e0d\u5728\u300c\u5b78\u751fB\u300d\u4e2d\u7684\u5b78\u751f\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n<pre><code>SELECT * FROM \u5b78\u751fA \nEXCEPT \nSELECT * FROM \u5b78\u751fB;<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-jwBkmjSxkY\">\u7d50\u8ad6<\/h2>\n<p>\u6578\u64da\u5eab\u95dc\u4fc2\u904b\u7b97\u4e2d\u7684\u904b\u7b97\u7b26\u865f\u662f\u6578\u64da\u64cd\u4f5c\u7684\u57fa\u790e\uff0c\u7406\u89e3\u9019\u4e9b\u904b\u7b97\u7b26\u865f\u7684\u529f\u80fd\u548c\u7528\u6cd5\u5c0d\u65bc\u6709\u6548\u5730\u7ba1\u7406\u548c\u67e5\u8a62\u6578\u64da\u81f3\u95dc\u91cd\u8981\u3002\u7121\u8ad6\u662f\u9078\u64c7\u3001\u6295\u5f71\u3001\u806f\u63a5\u9084\u662f\u5176\u4ed6\u904b\u7b97\uff0c\u9019\u4e9b\u5de5\u5177\u90fd\u80fd\u5e6b\u52a9\u7528\u6236\u66f4\u9ad8\u6548\u5730\u8655\u7406\u6578\u64da\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u6578\u64da\u5eab\u7ba1\u7406\u6709\u9032\u4e00\u6b65\u7684\u9700\u6c42\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u4f86\u642d\u5efa\u60a8\u7684\u6578\u64da\u5eab\u74b0\u5883\uff0c\u4eab\u53d7\u7a69\u5b9a\u548c\u9ad8\u6548\u7684\u670d\u52d9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6982\u8ff0\u6578\u64da\u5eab\u95dc\u4fc2\u904b\u7b97\u4e2d\u7684\u904b\u7b97\u7b26\u865f\uff0c\u63a2\u8a0e\u5176\u529f\u80fd\u8207\u61c9\u7528\uff0c\u5e6b\u52a9\u7406\u89e3\u6578\u64da\u67e5\u8a62\u8207\u7ba1\u7406\u7684\u57fa\u672c\u6982\u5ff5\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-186598","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186598","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=186598"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186598\/revisions"}],"predecessor-version":[{"id":186599,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/186598\/revisions\/186599"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=186598"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=186598"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=186598"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}