{"id":5262,"date":"2024-11-14T10:28:04","date_gmt":"2024-11-14T02:28:04","guid":{"rendered":"https:\/\/fwq.ai\/blog\/5262\/"},"modified":"2024-11-14T10:28:04","modified_gmt":"2024-11-14T02:28:04","slug":"mysql%e6%80%8e%e4%b9%88%e5%ae%9a%e4%b9%89%e5%8f%98%e9%87%8f","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/5262\/","title":{"rendered":"mysql\u600e\u4e48\u5b9a\u4e49\u53d8\u91cf"},"content":{"rendered":"<blockquote><p>\n  \u5728 mysql \u4e2d\u4f7f\u7528 declare \u548c set \u8bed\u53e5\u5b9a\u4e49\u53d8\u91cf\uff0c\u5176\u4e2d declare \u7528\u4e8e\u5b9a\u4e49\u53d8\u91cf\u540d\u79f0\u548c\u7c7b\u578b\uff0c\u800c set \u7528\u4e8e\u8d4b\u503c\u3002\u5177\u4f53\u6b65\u9aa4\u5305\u62ec\uff1a\u58f0\u660e\u53d8\u91cf\u540d\u79f0\u3001\u6570\u636e\u7c7b\u578b\u548c\u9ed8\u8ba4\u503c\uff1b\u4f7f\u7528 set \u8bed\u53e5\u4e3a\u53d8\u91cf\u8d4b\u503c\uff1b\u6ce8\u610f\u53d8\u91cf\u547d\u540d\u89c4\u5219\u548c\u6570\u636e\u7c7b\u578b\uff0c\u4e14\u53d8\u91cf\u4f5c\u7528\u57df\u4ec5\u9650\u4e8e\u5b9a\u4e49\u5b83\u4eec\u7684\u67e5\u8be2\u5757\u3002\n<\/p><\/blockquote>\n<p><img decoding=\"async\" src=\"https:\/\/img.php.cn\/upload\/article\/202405\/26\/2024052617544715396.jpg\" class=\"aligncenter\" title=\"mysql\u600e\u4e48\u5b9a\u4e49\u53d8\u91cf\u63d2\u56fe\" alt=\"mysql\u600e\u4e48\u5b9a\u4e49\u53d8\u91cf\u63d2\u56fe\" \/><\/p>\n<p><strong>\u5982\u4f55\u5728 MySQL \u4e2d\u5b9a\u4e49\u53d8\u91cf<\/strong><\/p>\n<p>MySQL \u4e2d\u5b9a\u4e49\u53d8\u91cf\u7684\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n<ol>\n<li>\n<p><strong>\u4f7f\u7528 DECLARE \u8bed\u53e5<\/strong><\/p>\n<pre>DECLARE &lt;\u53d8\u91cf\u540d&gt; &lt;\u6570\u636e\u7c7b\u578b&gt; [DEFAULT &lt;\u9ed8\u8ba4\u503c&gt;];<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre>DECLARE age INT DEFAULT 25;<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/li>\n<li>\n<p><strong>\u4f7f\u7528 SET \u8bed\u53e5<\/strong><\/p>\n<pre>SET &lt;\u53d8\u91cf\u540d&gt; = &lt;\u503c&gt;;<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u4f8b\u5982\uff1a<\/p>\n<pre>SET age = 30;<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/li>\n<\/ol>\n<p><strong>\u793a\u4f8b<\/strong><\/p>\n<p>\u4e0b\u9762\u7684\u793a\u4f8b\u6f14\u793a\u4e86\u5982\u4f55\u4f7f\u7528 DECLARE \u548c SET \u8bed\u53e5\u5b9a\u4e49\u548c\u4f7f\u7528\u53d8\u91cf\uff1a<\/p>\n<pre>DECLARE name VARCHAR(255) DEFAULT 'John Doe';\nSET age = 30;\n\nSELECT name, age;<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p>\u8f93\u51fa\uff1a<\/p>\n<pre>+-------------+------+\n| name         | age  |\n+-------------+------+\n| John Doe     | 30   |\n+-------------+------+<\/pre>\n<p> \u767b\u5f55\u540e\u590d\u5236 <\/p>\n<p><strong>\u6ce8\u610f\uff1a<\/strong><\/p>\n<ul>\n<li>\u53d8\u91cf\u540d\u79f0\u5fc5\u987b\u4ee5\u5b57\u6bcd\u6216\u4e0b\u5212\u7ebf\u5f00\u5934\uff0c\u5e76\u4e14\u4e0d\u80fd\u662f\u4fdd\u7559\u5173\u952e\u5b57\u3002<\/li>\n<li>\u53d8\u91cf\u6570\u636e\u7c7b\u578b\u53ef\u4ee5\u662f MySQL \u652f\u6301\u7684\u4efb\u4f55\u6570\u636e\u7c7b\u578b\u3002<\/li>\n<li>\u53d8\u91cf\u53ef\u4ee5\u968f\u65f6\u91cd\u65b0\u8d4b\u503c\u3002<\/li>\n<li>\u53d8\u91cf\u7684\u4ec5\u9650\u4e8e\u5b9a\u4e49\u5b83\u4eec\u7684\u67e5\u8be2\u5757\u3002<\/li>\n<\/ul>\n<p>\u4ee5\u4e0a\u5c31\u662f\u600e\u4e48\u5b9a\u4e49\u53d8\u91cf\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>\u5728 mysql \u4e2d\u4f7f\u7528 declare \u548c set \u8bed\u53e5\u5b9a\u4e49\u53d8\u91cf\uff0c\u5176\u4e2d declare \u7528\u4e8e\u5b9a\u4e49\u53d8\u91cf\u540d\u79f0\u548c\u7c7b\u578b\uff0c\u800c set \u7528\u4e8e\u8d4b\u503c\u3002\u5177\u4f53\u6b65\u9aa4\u5305\u62ec\uff1a\u58f0\u660e\u53d8\u91cf\u540d\u79f0\u3001\u6570\u636e\u7c7b\u578b\u548c\u9ed8\u8ba4\u503c\uff1b\u4f7f\u7528 set \u8bed\u53e5\u4e3a\u53d8\u91cf\u8d4b\u503c\uff1b\u6ce8\u610f\u53d8\u91cf\u547d\u540d\u89c4\u5219\u548c\u6570\u636e\u7c7b\u578b\uff0c\u4e14\u53d8\u91cf\u4f5c\u7528\u57df\u4ec5\u9650\u4e8e\u5b9a\u4e49\u5b83\u4eec\u7684\u67e5\u8be2\u5757\u3002 \u5982\u4f55\u5728 MySQL \u4e2d\u5b9a\u4e49\u53d8\u91cf MySQL \u4e2d\u5b9a\u4e49\u53d8\u91cf\u7684\u65b9\u6cd5\u5982\u4e0b\uff1a \u4f7f\u7528 DECLARE \u8bed\u53e5 DECLARE &lt;\u53d8\u91cf\u540d&gt; &lt;\u6570\u636e\u7c7b\u578b&gt; [DEFAULT &lt;\u9ed8\u8ba4\u503c&gt;]; \u767b\u5f55\u540e\u590d\u5236 \u4f8b\u5982\uff1a DECLARE age INT DEFAULT 25; \u767b\u5f55\u540e\u590d\u5236 \u4f7f\u7528 SET \u8bed\u53e5 SET &lt;\u53d8\u91cf\u540d&gt; = &lt;\u503c&gt;; \u767b\u5f55\u540e\u590d\u5236 \u4f8b\u5982\uff1a SET age = 30; \u767b\u5f55\u540e\u590d\u5236 \u793a\u4f8b \u4e0b\u9762\u7684\u793a\u4f8b\u6f14\u793a\u4e86\u5982\u4f55\u4f7f\u7528 DECLARE \u548c SET \u8bed\u53e5\u5b9a\u4e49\u548c\u4f7f\u7528\u53d8\u91cf\uff1a DECLARE [&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-5262","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5262","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=5262"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/5262\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=5262"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=5262"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=5262"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}