{"id":60863,"date":"2024-10-13T06:27:12","date_gmt":"2024-10-12T22:27:12","guid":{"rendered":"https:\/\/server.hk\/cnblog\/60863\/"},"modified":"2024-10-13T06:27:12","modified_gmt":"2024-10-12T22:27:12","slug":"db2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%adselect%e8%aa%9e%e5%8f%a5%e7%9a%84%e7%94%a8%e6%b3%95%e6%9c%89%e5%93%aa%e4%ba%9b%ef%bc%9f%e6%95%88%e6%9e%9c%e5%a6%82%e4%bd%95%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/60863\/","title":{"rendered":"DB2\u6578\u64da\u5eab\u4e2dSELECT\u8a9e\u53e5\u7684\u7528\u6cd5\u6709\u54ea\u4e9b\uff1f\u6548\u679c\u5982\u4f55\uff1f"},"content":{"rendered":"<h1 id=\"db2%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%adselect%e8%aa%9e%e5%8f%a5%e7%9a%84%e7%94%a8%e6%b3%95%e6%9c%89%e5%93%aa%e4%ba%9b%ef%bc%9f%e6%95%88%e6%9e%9c%e5%a6%82%e4%bd%95%ef%bc%9f-wQzrdzOVIl\">DB2\u6578\u64da\u5eab\u4e2dSELECT\u8a9e\u53e5\u7684\u7528\u6cd5\u6709\u54ea\u4e9b\uff1f\u6548\u679c\u5982\u4f55\uff1f<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u7528\u65bc\u67e5\u8a62\u548c\u64cd\u4f5c\u6578\u64da\u7684\u4e3b\u8981\u8a9e\u8a00\u3002IBM\u7684DB2\u6578\u64da\u5eab\u7cfb\u7d71\u652f\u6301SQL\uff0c\u4e26\u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\u5f37\u5927\u7684SELECT\u8a9e\u53e5\u7528\u6cd5\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eDB2\u6578\u64da\u5eab\u4e2dSELECT\u8a9e\u53e5\u7684\u7528\u6cd5\u53ca\u5176\u6548\u679c\u3002<\/p>\n<h2 id=\"select%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%9f%ba%e6%9c%ac%e7%b5%90%e6%a7%8b-wQzrdzOVIl\">SELECT\u8a9e\u53e5\u7684\u57fa\u672c\u7d50\u69cb<\/h2>\n<p>SELECT\u8a9e\u53e5\u7684\u57fa\u672c\u7d50\u69cb\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT column1, column2, ...\nFROM table_name\nWHERE condition;<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>column1, column2, ...<\/code>\u662f\u8981\u67e5\u8a62\u7684\u5217\uff0c<code>table_name<\/code>\u662f\u6578\u64da\u8868\u7684\u540d\u7a31\uff0c\u800c<code>condition<\/code>\u5247\u662f\u904e\u6ffe\u689d\u4ef6\u3002\u9019\u7a2e\u7d50\u69cb\u4f7f\u5f97\u7528\u6236\u80fd\u5920\u9748\u6d3b\u5730\u5f9e\u6578\u64da\u5eab\u4e2d\u63d0\u53d6\u6240\u9700\u7684\u4fe1\u606f\u3002<\/p>\n<h2 id=\"select%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%a4%9a%e7%a8%ae%e7%94%a8%e6%b3%95-wQzrdzOVIl\">SELECT\u8a9e\u53e5\u7684\u591a\u7a2e\u7528\u6cd5<\/h2>\n<h3 id=\"1-%e5%9f%ba%e6%9c%ac%e6%9f%a5%e8%a9%a2-wQzrdzOVIl\">1. \u57fa\u672c\u67e5\u8a62<\/h3>\n<p>\u6700\u57fa\u672c\u7684SELECT\u8a9e\u53e5\u7528\u6cd5\u662f\u5f9e\u4e00\u500b\u8868\u4e2d\u9078\u64c7\u6240\u6709\u5217\u7684\u6578\u64da\uff1a<\/p>\n<pre><code>SELECT * FROM employees;<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de<code>employees<\/code>\u8868\u4e2d\u7684\u6240\u6709\u884c\u548c\u5217\u3002<\/p>\n<h3 id=\"2-%e9%81%8e%e6%bf%be%e6%9f%a5%e8%a9%a2-wQzrdzOVIl\">2. \u904e\u6ffe\u67e5\u8a62<\/h3>\n<p>\u4f7f\u7528<code>WHERE<\/code>\u5b50\u53e5\u53ef\u4ee5\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u904e\u6ffe\u67e5\u8a62\u7d50\u679c\uff1a<\/p>\n<pre><code>SELECT * FROM employees\nWHERE department = 'Sales';<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u6240\u6709\u5728\u92b7\u552e\u90e8\u9580\u5de5\u4f5c\u7684\u54e1\u5de5\u3002<\/p>\n<h3 id=\"3-%e6%8e%92%e5%ba%8f%e6%9f%a5%e8%a9%a2-wQzrdzOVIl\">3. \u6392\u5e8f\u67e5\u8a62<\/h3>\n<p>\u53ef\u4ee5\u4f7f\u7528<code>ORDER BY<\/code>\u5b50\u53e5\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u6392\u5e8f\uff1a<\/p>\n<pre><code>SELECT * FROM employees\nORDER BY last_name ASC;<\/code><\/pre>\n<p>\u9019\u5c07\u6839\u64da\u54e1\u5de5\u7684\u59d3\u6c0f\u6309\u5347\u5e8f\u6392\u5217\u7d50\u679c\u3002<\/p>\n<h3 id=\"4-%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-wQzrdzOVIl\">4. \u805a\u5408\u51fd\u6578<\/h3>\n<p>DB2\u652f\u6301\u591a\u7a2e\u805a\u5408\u51fd\u6578\uff0c\u5982<code>COUNT<\/code>\u3001<code>SUM<\/code>\u3001<code>AVG<\/code>\u7b49\uff0c\u53ef\u4ee5\u7528\u65bc\u7d71\u8a08\u6578\u64da\uff1a<\/p>\n<pre><code>SELECT COUNT(*) FROM employees\nWHERE department = 'Sales';<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u92b7\u552e\u90e8\u9580\u54e1\u5de5\u7684\u7e3d\u6578\u3002<\/p>\n<h3 id=\"5-%e5%88%86%e7%b5%84%e6%9f%a5%e8%a9%a2-wQzrdzOVIl\">5. \u5206\u7d44\u67e5\u8a62<\/h3>\n<p>\u4f7f\u7528<code>GROUP BY<\/code>\u5b50\u53e5\u53ef\u4ee5\u5c0d\u67e5\u8a62\u7d50\u679c\u9032\u884c\u5206\u7d44\uff1a<\/p>\n<pre><code>SELECT department, COUNT(*) FROM employees\nGROUP BY department;<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u6bcf\u500b\u90e8\u9580\u7684\u54e1\u5de5\u6578\u91cf\u3002<\/p>\n<h3 id=\"6-%e9%80%a3%e6%8e%a5%e6%9f%a5%e8%a9%a2-wQzrdzOVIl\">6. \u9023\u63a5\u67e5\u8a62<\/h3>\n<p>DB2\u652f\u6301\u591a\u7a2e\u9023\u63a5\u64cd\u4f5c\uff0c\u53ef\u4ee5\u5f9e\u591a\u500b\u8868\u4e2d\u63d0\u53d6\u6578\u64da\uff1a<\/p>\n<pre><code>SELECT e.first_name, e.last_name, d.department_name\nFROM employees e\nJOIN departments d ON e.department_id = d.id;<\/code><\/pre>\n<p>\u9019\u5c07\u8fd4\u56de\u54e1\u5de5\u7684\u59d3\u540d\u53ca\u5176\u6240\u5c6c\u90e8\u9580\u7684\u540d\u7a31\u3002<\/p>\n<h2 id=\"select%e8%aa%9e%e5%8f%a5%e7%9a%84%e6%95%88%e6%9e%9c-wQzrdzOVIl\">SELECT\u8a9e\u53e5\u7684\u6548\u679c<\/h2>\n<p>\u4f7f\u7528SELECT\u8a9e\u53e5\u53ef\u4ee5\u9ad8\u6548\u5730\u5f9eDB2\u6578\u64da\u5eab\u4e2d\u63d0\u53d6\u548c\u5206\u6790\u6578\u64da\u3002\u901a\u904e\u9748\u6d3b\u7684\u67e5\u8a62\u689d\u4ef6\u548c\u805a\u5408\u51fd\u6578\uff0c\u7528\u6236\u80fd\u5920\u7372\u5f97\u6240\u9700\u7684\u4fe1\u606f\uff0c\u9032\u800c\u652f\u6301\u696d\u52d9\u6c7a\u7b56\u3002DB2\u7684\u67e5\u8a62\u512a\u5316\u5668\u80fd\u5920\u81ea\u52d5\u9078\u64c7\u6700\u4f73\u7684\u57f7\u884c\u8a08\u5283\uff0c\u5f9e\u800c\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-wQzrdzOVIl\">\u7e3d\u7d50<\/h2>\n<p>DB2\u6578\u64da\u5eab\u4e2d\u7684SELECT\u8a9e\u53e5\u63d0\u4f9b\u4e86\u591a\u7a2e\u9748\u6d3b\u7684\u7528\u6cd5\uff0c\u5f9e\u57fa\u672c\u67e5\u8a62\u5230\u8907\u96dc\u7684\u9023\u63a5\u67e5\u8a62\uff0c\u5747\u80fd\u6709\u6548\u5730\u6eff\u8db3\u7528\u6236\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f\u9032\u884c\u6578\u64da\u5206\u6790\u9084\u662f\u652f\u6301\u696d\u52d9\u6c7a\u7b56\uff0cSELECT\u8a9e\u53e5\u90fd\u662f\u4e0d\u53ef\u6216\u7f3a\u7684\u5de5\u5177\u3002\u82e5\u60a8\u9700\u8981\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\u4f86\u642d\u5efa\u60a8\u7684DB2\u74b0\u5883\uff0c\u4eab\u53d7\u7a69\u5b9a\u7684\u6027\u80fd\u548c\u5b89\u5168\u7684\u6578\u64da\u7ba1\u7406\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22DB2\u6578\u64da\u5eab\u4e2dSELECT\u8a9e\u53e5\u7684\u591a\u7a2e\u7528\u6cd5\u53ca\u5176\u6548\u679c\uff0c\u4e86\u89e3\u5982\u4f55\u9ad8\u6548\u67e5\u8a62\u548c\u7ba1\u7406\u6578\u64da\u3002<\/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-60863","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60863","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=60863"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60863\/revisions"}],"predecessor-version":[{"id":60864,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60863\/revisions\/60864"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=60863"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=60863"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=60863"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}