{"id":5923,"date":"2024-11-14T11:09:38","date_gmt":"2024-11-14T03:09:38","guid":{"rendered":"https:\/\/fwq.ai\/blog\/5923\/"},"modified":"2024-11-14T11:09:38","modified_gmt":"2024-11-14T03:09:38","slug":"sql%e6%80%8e%e4%b9%88%e6%8a%8a%e5%a4%9a%e8%a1%8c%e6%98%be%e7%a4%ba%e4%b8%ba%e4%b8%80%e8%a1%8c","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/5923\/","title":{"rendered":"sql\u600e\u4e48\u628a\u591a\u884c\u663e\u793a\u4e3a\u4e00\u884c"},"content":{"rendered":"<blockquote><p>\n  sql \u4e2d\u5c06\u591a\u884c\u6570\u636e\u5408\u5e76\u4e3a\u4e00\u884c\u7684\u6280\u5de7\u5305\u62ec\uff1a\u4f7f\u7528 concat \u51fd\u6570\u8fde\u63a5\u5b57\u7b26\u4e32\uff0c\u5982\u5c06\u59d3\u540d\u5206\u7ec4\u6210\u5168\u540d\u3002\u4f7f\u7528 group_concat \u51fd\u6570\u8fde\u63a5\u7ec4\u4e2d\u6240\u6709\u884c\u7684\u503c\uff0c\u5982\u5c06\u4ea7\u54c1\u5217\u8868\u5206\u7ec4\u3002\u4f7f\u7528 string_agg \u51fd\u6570\u8fde\u63a5\u5b57\u7b26\u4e32\u5e76\u6307\u5b9a\u5206\u9694\u7b26\uff0c\u5982\u5c06\u6280\u80fd\u5217\u8868\u5206\u7ec4\u5e76\u6dfb\u52a0\u5206\u9694\u7b26\u3002\u4f7f\u7528 for xml path(&#8221;) \u5b50\u53e5\u5c06\u67e5\u8be2\u7ed3\u679c\u8f6c\u6362\u4e3a xml \u5b57\u7b26\u4e32\u3002\u4f7f\u7528 stuff \u51fd\u6570\u63d2\u5165\u5b50\u5b57\u7b26\u4e32\uff0c\u5982\u5c06\u5ba2\u6237\u59d3\u540d\u8f6c\u6362\u4e3a\u5e26\u6709 xml \u6807\u8bb0\u7684\u884c\u3002\n<\/p><\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/202406\/03\/2024060322305216444.jpg\" class=\"aligncenter\" title=\"sql\u600e\u4e48\u628a\u591a\u884c\u663e\u793a\u4e3a\u4e00\u884c\u63d2\u56fe\" alt=\"sql\u600e\u4e48\u628a\u591a\u884c\u663e\u793a\u4e3a\u4e00\u884c\u63d2\u56fe\" \/><\/p>\n<p><strong>SQL \u4e2d\u5c06\u591a\u884c\u663e\u793a\u4e3a\u4e00\u884c\u7684\u6280\u5de7<\/strong><\/p>\n<p>\u5728 SQL \u67e5\u8be2\u4e2d\uff0c\u5c06\u591a\u884c\u6570\u636e\u7c98\u5408\u6210\u4e00\u884c\u53ef\u4ee5\u63d0\u9ad8\u53ef\u8bfb\u6027\u548c\u53ef\u7ba1\u7406\u6027\u3002\u6709\u51e0\u79cd\u65b9\u6cd5\u53ef\u4ee5\u5b9e\u73b0\u6b64\u76ee\u7684\uff0c\u4e0b\u9762\u5217\u51fa\u4e86\u4e00\u4e9b\u6700\u5e38\u7528\u7684\uff1a<\/p>\n<p><strong>1. CONCAT \u51fd\u6570<\/strong><\/p>\n<p>CONCAT() \u51fd\u6570\u53ef\u4ee5\u5c06\u591a\u4e2a\u5b57\u7b26\u4e32\u8fde\u63a5\u8d77\u6765\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u8868 customer \u4e2d\u7684 first_name\u3001middle_name \u548c last_name \u5217\u8fde\u63a5\u5230\u4e00\u884c\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n<pre>SELECT CONCAT(first_name, ' ', middle_name, ' ', last_name) AS full_name\nFROM customer;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p><strong>2. GROUP_CONCAT \u51fd\u6570<\/strong><\/p>\n<p>GROUP_CONCAT() \u51fd\u6570\u53ef\u5c06\u7ec4\u4e2d\u6240\u6709\u884c\u7684\u503c\u8fde\u63a5\u6210\u4e00\u4e2a\u5b57\u7b26\u4e32\u3002\u5b83\u901a\u5e38\u4e0e GROUP BY \u5b50\u53e5\u4e00\u8d77\u4f7f\u7528\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u8868 order \u4e2d\u7684 product_name \u5217\u5206\u7ec4\u5e76\u663e\u793a\u5728\u6bcf\u4e00\u884c\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n<pre>SELECT product_category, GROUP_CONCAT(product_name) AS product_list\nFROM order\nGROUP BY product_category;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p><strong>3. STRING_AGG \u51fd\u6570<\/strong><\/p>\n<p>STRING_AGG() \u51fd\u6570\u662f GROUP_CONCAT() \u51fd\u6570\u7684\u589e\u5f3a\u7248\uff0c\u5b83\u5141\u8bb8\u66f4\u7075\u6d3b\u5730\u8fde\u63a5\u5b57\u7b26\u4e32\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u8868 employee \u4e2d\u7684 skill \u5217\u5206\u7ec4\u5e76\u663e\u793a\u4e3a\u5e26\u5206\u9694\u7b26\u7684\u5217\u8868\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n<pre>SELECT department, STRING_AGG(skill, ', ') AS skill_set\nFROM employee\nGROUP BY department;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p><strong>4. FOR XML PATH(&#8221;)<\/strong><\/p>\n<p>FOR XML PATH(&#8221;) \u5b50\u53e5\u53ef\u4ee5\u5c06\u67e5\u8be2\u7ed3\u679c\u8f6c\u6362\u4e3a XML \u683c\u5f0f\uff0c\u7136\u540e\u5c06\u5176\u663e\u793a\u4e3a\u5355\u884c\u5b57\u7b26\u4e32\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u8868 invoice \u4e2d\u7684\u6240\u6709\u884c\u8f6c\u6362\u4e3a\u4e00\u884c XML \u5b57\u7b26\u4e32\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n<pre>SELECT *\nFROM invoice\nFOR XML PATH('');<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p><strong>5. STUFF \u51fd\u6570<\/strong><\/p>\n<p>STUFF() \u51fd\u6570\u53ef\u4ee5\u5c06\u6307\u5b9a\u957f\u5ea6\u7684\u5b50\u5b57\u7b26\u4e32\u63d2\u5165\u5230\u73b0\u6709\u5b57\u7b26\u4e32\u4e2d\u3002\u5b83\u901a\u5e38\u4e0e FOR XML PATH(&#8221;) \u5b50\u53e5\u7ed3\u5408\u4f7f\u7528\uff0c\u4ee5\u63d2\u5165 XML \u6807\u8bb0\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u8868 customer \u4e2d\u7684 first_name \u548c last_name \u5217\u8f6c\u6362\u4e3a\u5e26\u6709 XML \u6807\u8bb0\u7684\u884c\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n<pre>SELECT STUFF((\n  SELECT ',&lt;Name&gt;' + first_name + '&lt;\/Name&gt;'\n  FROM customer\n  FOR XML PATH('')\n), 1, 1, '&lt;Customer&gt;') AS customer_list;<\/pre>\n<p>  \u767b\u5f55\u540e\u590d\u5236   <\/p>\n<p>\u4ee5\u4e0a\u5c31\u662fsql\u600e\u4e48\u628a\u591a\u884c\u663e\u793a\u4e3a\u4e00\u884c\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>sql \u4e2d\u5c06\u591a\u884c\u6570\u636e\u5408\u5e76\u4e3a\u4e00\u884c\u7684\u6280\u5de7\u5305\u62ec\uff1a\u4f7f\u7528 concat \u51fd\u6570\u8fde\u63a5\u5b57\u7b26\u4e32\uff0c\u5982\u5c06\u59d3\u540d\u5206\u7ec4\u6210\u5168\u540d\u3002\u4f7f\u7528 group_concat \u51fd\u6570\u8fde\u63a5\u7ec4\u4e2d\u6240\u6709\u884c\u7684\u503c\uff0c\u5982\u5c06\u4ea7\u54c1\u5217\u8868\u5206\u7ec4\u3002\u4f7f\u7528 string_agg \u51fd\u6570\u8fde\u63a5\u5b57\u7b26\u4e32\u5e76\u6307\u5b9a\u5206\u9694\u7b26\uff0c\u5982\u5c06\u6280\u80fd\u5217\u8868\u5206\u7ec4\u5e76\u6dfb\u52a0\u5206\u9694\u7b26\u3002\u4f7f\u7528 for xml path(&#8221;) \u5b50\u53e5\u5c06\u67e5\u8be2\u7ed3\u679c\u8f6c\u6362\u4e3a xml \u5b57\u7b26\u4e32\u3002\u4f7f\u7528 stuff \u51fd\u6570\u63d2\u5165\u5b50\u5b57\u7b26\u4e32\uff0c\u5982\u5c06\u5ba2\u6237\u59d3\u540d\u8f6c\u6362\u4e3a\u5e26\u6709 xml \u6807\u8bb0\u7684\u884c\u3002 SQL \u4e2d\u5c06\u591a\u884c\u663e\u793a\u4e3a\u4e00\u884c\u7684\u6280\u5de7 \u5728 SQL \u67e5\u8be2\u4e2d\uff0c\u5c06\u591a\u884c\u6570\u636e\u7c98\u5408\u6210\u4e00\u884c\u53ef\u4ee5\u63d0\u9ad8\u53ef\u8bfb\u6027\u548c\u53ef\u7ba1\u7406\u6027\u3002\u6709\u51e0\u79cd\u65b9\u6cd5\u53ef\u4ee5\u5b9e\u73b0\u6b64\u76ee\u7684\uff0c\u4e0b\u9762\u5217\u51fa\u4e86\u4e00\u4e9b\u6700\u5e38\u7528\u7684\uff1a 1. CONCAT \u51fd\u6570 CONCAT() \u51fd\u6570\u53ef\u4ee5\u5c06\u591a\u4e2a\u5b57\u7b26\u4e32\u8fde\u63a5\u8d77\u6765\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u8868 customer \u4e2d\u7684 first_name\u3001middle_name \u548c last_name \u5217\u8fde\u63a5\u5230\u4e00\u884c\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\uff1a SELECT CONCAT(first_name, &#8216; &#8216;, middle_name, &#8216; &#8216;, last_name) AS full_name FROM customer; \u767b\u5f55\u540e\u590d\u5236 2. GROUP_CONCAT \u51fd\u6570 GROUP_CONCAT() \u51fd\u6570\u53ef\u5c06\u7ec4\u4e2d\u6240\u6709\u884c\u7684\u503c\u8fde\u63a5\u6210\u4e00\u4e2a\u5b57\u7b26\u4e32\u3002\u5b83\u901a\u5e38\u4e0e GROUP BY \u5b50\u53e5\u4e00\u8d77\u4f7f\u7528\u3002\u4f8b\u5982\uff0c\u8981\u5c06\u8868 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-5923","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5923","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=5923"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5923\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=5923"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=5923"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=5923"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}