{"id":1796,"date":"2025-02-18T22:57:29","date_gmt":"2025-02-18T14:57:29","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=1796"},"modified":"2025-02-18T22:57:29","modified_gmt":"2025-02-18T14:57:29","slug":"mysql-%e5%a4%8d%e5%88%b6%e8%a1%a8","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/02\/18\/mysql-%e5%a4%8d%e5%88%b6%e8%a1%a8\/","title":{"rendered":"MySQL \u590d\u5236\u8868"},"content":{"rendered":"\n<p>MySQL \u590d\u5236\u8868\u662f\u5c06\u4e00\u4e2a\u8868\u7684\u7ed3\u6784\u548c\u6570\u636e\u590d\u5236\u5230\u53e6\u4e00\u4e2a\u8868\u4e2d\uff0c\u8fd9\u5bf9\u4e8e\u6570\u636e\u5e93\u5907\u4efd\u3001\u6570\u636e\u8fc1\u79fb\u3001\u6570\u636e\u540c\u6b65\u7b49\u64cd\u4f5c\u975e\u5e38\u6709\u7528\u3002\u590d\u5236\u8868\u53ef\u4ee5\u5206\u4e3a\u4e24\u79cd\u65b9\u5f0f\uff1a\u4e00\u79cd\u662f\u590d\u5236\u8868\u7ed3\u6784\uff08\u4e0d\u5305\u542b\u6570\u636e\uff09\uff0c\u53e6\u4e00\u79cd\u662f\u590d\u5236\u8868\u7ed3\u6784\u548c\u6570\u636e\u3002\u8fd9\u91cc\u5c06\u8be6\u7ec6\u8bb2\u89e3\u5982\u4f55\u8fdb\u884c\u8868\u590d\u5236\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u7684\u5b9e\u4f8b\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">1. <strong>\u590d\u5236\u8868\u7684\u57fa\u672c\u65b9\u6cd5<\/strong><\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1.1 \u590d\u5236\u8868\u7ed3\u6784\uff08\u4e0d\u590d\u5236\u6570\u636e\uff09<\/h4>\n\n\n\n<p>\u5982\u679c\u4f60\u53ea\u60f3\u590d\u5236\u8868\u7684\u7ed3\u6784\u800c\u4e0d\u5305\u62ec\u6570\u636e\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>CREATE TABLE<\/code> \u8bed\u53e5\u7ed3\u5408 <code>LIKE<\/code> \u5173\u952e\u5b57\u6765\u590d\u5236\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE new_table LIKE old_table;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>new_table<\/code> \u662f\u65b0\u521b\u5efa\u7684\u8868\u7684\u540d\u5b57\u3002<\/li>\n\n\n\n<li><code>old_table<\/code> \u662f\u4f60\u60f3\u590d\u5236\u7684\u8868\u7684\u540d\u5b57\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u6b64\u65b9\u6cd5\u4f1a\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u8868 <code>new_table<\/code>\uff0c\u5b83\u5177\u6709\u4e0e <code>old_table<\/code> \u76f8\u540c\u7684\u8868\u7ed3\u6784\uff0c\u4f46\u4e0d\u5305\u542b\u4efb\u4f55\u6570\u636e\uff0c\u4e5f\u4e0d\u4f1a\u590d\u5236\u7d22\u5f15\u3001\u4e3b\u952e\u6216\u5916\u952e\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u590d\u5236\u8868\u7ed3\u6784<\/h4>\n\n\n\n<p>\u5047\u8bbe\u4f60\u6709\u4e00\u4e2a\u540d\u4e3a <code>employees<\/code> \u7684\u8868\uff0c\u4f60\u60f3\u521b\u5efa\u4e00\u4e2a\u540d\u4e3a <code>employees_backup<\/code> \u7684\u8868\uff0c\u53ea\u590d\u5236\u8868\u7ed3\u6784\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE employees_backup LIKE employees;<\/code><\/pre>\n\n\n\n<p>\u6267\u884c\u8be5\u547d\u4ee4\u540e\uff0c<code>employees_backup<\/code> \u5c06\u5177\u6709\u4e0e <code>employees<\/code> \u76f8\u540c\u7684\u5217\u548c\u6570\u636e\u7c7b\u578b\uff0c\u4f46\u6ca1\u6709\u4efb\u4f55\u6570\u636e\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">1.2 \u590d\u5236\u8868\u7ed3\u6784\u548c\u6570\u636e<\/h4>\n\n\n\n<p>\u5982\u679c\u4f60\u60f3\u590d\u5236\u8868\u7684\u7ed3\u6784\u548c\u6570\u636e\uff0c\u53ef\u4ee5\u7ed3\u5408 <code>CREATE TABLE<\/code> \u548c <code>INSERT INTO<\/code> \u8bed\u53e5\u6765\u5b8c\u6210\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE new_table AS SELECT * FROM old_table;<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>new_table<\/code> \u662f\u65b0\u521b\u5efa\u7684\u8868\u7684\u540d\u5b57\u3002<\/li>\n\n\n\n<li><code>old_table<\/code> \u662f\u4f60\u60f3\u590d\u5236\u7684\u8868\u7684\u540d\u5b57\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u79cd\u65b9\u6cd5\u4f1a\u5c06 <code>old_table<\/code> \u7684\u6570\u636e\u63d2\u5165\u5230 <code>new_table<\/code> \u4e2d\uff0c\u5e76\u590d\u5236\u8868\u7684\u7ed3\u6784\u3002\u5982\u679c\u4f60\u53ea\u5e0c\u671b\u590d\u5236\u90e8\u5206\u6570\u636e\uff0c\u53ef\u4ee5\u5728 <code>SELECT<\/code> \u8bed\u53e5\u4e2d\u4f7f\u7528 <code>WHERE<\/code> \u5b50\u53e5\u8fdb\u884c\u8fc7\u6ee4\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u590d\u5236\u8868\u7ed3\u6784\u548c\u6570\u636e<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE employees_backup AS SELECT * FROM employees;<\/code><\/pre>\n\n\n\n<p>\u8fd9\u6761\u547d\u4ee4\u5c06\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u8868 <code>employees_backup<\/code>\uff0c\u5176\u7ed3\u6784\u548c\u6570\u636e\u4e0e <code>employees<\/code> \u5b8c\u5168\u76f8\u540c\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2. <strong>\u590d\u5236\u90e8\u5206\u6570\u636e<\/strong><\/h3>\n\n\n\n<p>\u4f60\u4e5f\u53ef\u4ee5\u5728\u590d\u5236\u6570\u636e\u65f6\u6839\u636e\u7279\u5b9a\u7684\u6761\u4ef6\u9009\u62e9\u8981\u590d\u5236\u7684\u6570\u636e\u3002\u8fd9\u53ef\u4ee5\u901a\u8fc7 <code>WHERE<\/code> \u5b50\u53e5\u6765\u5b9e\u73b0\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u590d\u5236\u7279\u5b9a\u6570\u636e<\/h4>\n\n\n\n<p>\u5047\u8bbe\u4f60\u53ea\u60f3\u590d\u5236 <code>employees<\/code> \u8868\u4e2d\u85aa\u8d44\u5927\u4e8e 50000 \u7684\u5458\u5de5\u6570\u636e\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE employees_high_salary AS \nSELECT * FROM employees WHERE emp_salary &gt; 50000;<\/code><\/pre>\n\n\n\n<p>\u6267\u884c\u540e\uff0c<code>employees_high_salary<\/code> \u8868\u5c06\u4ec5\u5305\u542b\u85aa\u8d44\u5927\u4e8e 50000 \u7684\u5458\u5de5\u6570\u636e\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3. <strong>\u590d\u5236\u8868\u5e76\u4fee\u6539\u7ed3\u6784<\/strong><\/h3>\n\n\n\n<p>\u5982\u679c\u4f60\u5e0c\u671b\u590d\u5236\u8868\u5e76\u5728\u590d\u5236\u8fc7\u7a0b\u4e2d\u4fee\u6539\u5176\u7ed3\u6784\uff08\u6bd4\u5982\u4fee\u6539\u6570\u636e\u7c7b\u578b\u3001\u589e\u52a0\u6216\u5220\u9664\u5217\uff09\uff0c\u53ef\u4ee5\u5728\u590d\u5236\u8868\u540e\u4f7f\u7528 <code>ALTER TABLE<\/code> \u6765\u8fdb\u884c\u4fee\u6539\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u590d\u5236\u5e76\u4fee\u6539\u7ed3\u6784<\/h4>\n\n\n\n<p>\u5047\u8bbe\u4f60\u60f3\u590d\u5236 <code>employees<\/code> \u8868\uff0c\u5e76\u5c06\u65b0\u8868\u7684 <code>emp_salary<\/code> \u5217\u7684\u6570\u636e\u7c7b\u578b\u66f4\u6539\u4e3a <code>DECIMAL(12, 2)<\/code>\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE employees_backup AS SELECT * FROM employees;\nALTER TABLE employees_backup MODIFY COLUMN emp_salary DECIMAL(12, 2);<\/code><\/pre>\n\n\n\n<p>\u8fd9\u6761\u547d\u4ee4\u5148\u590d\u5236\u4e86\u8868\u7ed3\u6784\u548c\u6570\u636e\uff0c\u7136\u540e\u4fee\u6539\u4e86\u65b0\u8868\u4e2d <code>emp_salary<\/code> \u5217\u7684\u7c7b\u578b\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4. <strong>\u590d\u5236\u8868\u5e76\u6dfb\u52a0\u7d22\u5f15<\/strong><\/h3>\n\n\n\n<p>\u5728\u590d\u5236\u8868\u540e\uff0c\u4f60\u53ef\u80fd\u8fd8\u60f3\u6dfb\u52a0\u7d22\u5f15\u6216\u7ea6\u675f\u6765\u4f18\u5316\u67e5\u8be2\u6027\u80fd\u3002\u4f60\u53ef\u4ee5\u4f7f\u7528 <code>CREATE INDEX<\/code> \u8bed\u53e5\u4e3a\u65b0\u8868\u521b\u5efa\u7d22\u5f15\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u590d\u5236\u8868\u5e76\u6dfb\u52a0\u7d22\u5f15<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE employees_backup AS SELECT * FROM employees;\nCREATE INDEX idx_emp_name ON employees_backup (emp_name);<\/code><\/pre>\n\n\n\n<p>\u8fd9\u91cc\u6211\u4eec\u5148\u590d\u5236\u4e86\u8868 <code>employees<\/code>\uff0c\u7136\u540e\u4e3a\u65b0\u8868 <code>employees_backup<\/code> \u7684 <code>emp_name<\/code> \u5217\u521b\u5efa\u4e86\u7d22\u5f15 <code>idx_emp_name<\/code>\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">5. <strong>\u590d\u5236\u8868\u5e76\u4f7f\u7528\u81ea\u5b9a\u4e49\u6570\u636e<\/strong><\/h3>\n\n\n\n<p>\u4f60\u53ef\u4ee5\u5728\u590d\u5236\u8868\u65f6\u4f7f\u7528\u81ea\u5b9a\u4e49\u7684\u6570\u636e\uff0c\u5982\u4fee\u6539\u5b57\u6bb5\u503c\u6216\u6dfb\u52a0\u8ba1\u7b97\u5217\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u590d\u5236\u8868\u5e76\u4fee\u6539\u5b57\u6bb5\u503c<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE employees_backup AS \nSELECT emp_id, CONCAT(emp_first_name, ' ', emp_last_name) AS full_name, emp_salary \nFROM employees;<\/code><\/pre>\n\n\n\n<p>\u5728\u8fd9\u4e2a\u793a\u4f8b\u4e2d\uff0c\u6211\u4eec\u5c06 <code>employees<\/code> \u8868\u7684 <code>emp_first_name<\/code> \u548c <code>emp_last_name<\/code> \u5217\u5408\u5e76\u4e3a <code>full_name<\/code> \u5217\uff0c\u5e76\u5c06\u7ed3\u679c\u590d\u5236\u5230 <code>employees_backup<\/code> \u4e2d\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">6. <strong>\u5220\u9664\u590d\u5236\u7684\u8868<\/strong><\/h3>\n\n\n\n<p>\u4e00\u65e6\u4e0d\u518d\u9700\u8981\u590d\u5236\u7684\u8868\uff0c\u53ef\u4ee5\u901a\u8fc7 <code>DROP TABLE<\/code> \u5220\u9664\u5b83\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u793a\u4f8b\uff1a\u5220\u9664\u8868<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>DROP TABLE employees_backup;<\/code><\/pre>\n\n\n\n<p>\u8fd9\u6761\u547d\u4ee4\u5c06\u5220\u9664\u540d\u4e3a <code>employees_backup<\/code> \u7684\u8868\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">7. <strong>\u603b\u7ed3<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u590d\u5236\u8868\u7ed3\u6784<\/strong>\uff1a\u4f7f\u7528 <code>CREATE TABLE new_table LIKE old_table<\/code> \u590d\u5236\u8868\u7ed3\u6784\u3002<\/li>\n\n\n\n<li><strong>\u590d\u5236\u8868\u7ed3\u6784\u548c\u6570\u636e<\/strong>\uff1a\u4f7f\u7528 <code>CREATE TABLE new_table AS SELECT * FROM old_table<\/code> \u590d\u5236\u8868\u7ed3\u6784\u548c\u6570\u636e\u3002<\/li>\n\n\n\n<li><strong>\u590d\u5236\u90e8\u5206\u6570\u636e<\/strong>\uff1a\u53ef\u4ee5\u901a\u8fc7 <code>WHERE<\/code> \u5b50\u53e5\u8fc7\u6ee4\u6570\u636e\u6765\u590d\u5236\u90e8\u5206\u6570\u636e\u3002<\/li>\n\n\n\n<li><strong>\u4fee\u6539\u8868\u7ed3\u6784<\/strong>\uff1a\u5728\u590d\u5236\u8868\u540e\u53ef\u4ee5\u4f7f\u7528 <code>ALTER TABLE<\/code> \u4fee\u6539\u8868\u7ed3\u6784\u3002<\/li>\n\n\n\n<li><strong>\u6dfb\u52a0\u7d22\u5f15<\/strong>\uff1a\u5728\u590d\u5236\u8868\u540e\u53ef\u4ee5\u4f7f\u7528 <code>CREATE INDEX<\/code> \u521b\u5efa\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>\u5220\u9664\u8868<\/strong>\uff1a\u4e0d\u518d\u9700\u8981\u65f6\u53ef\u4ee5\u4f7f\u7528 <code>DROP TABLE<\/code> \u5220\u9664\u8868\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u901a\u8fc7\u8fd9\u4e9b\u64cd\u4f5c\uff0c\u53ef\u4ee5\u6839\u636e\u9700\u6c42\u7075\u6d3b\u5730\u590d\u5236\u8868\u3001\u4fee\u6539\u8868\u7ed3\u6784\u548c\u6570\u636e\uff0c\u5b9e\u73b0\u591a\u79cd\u6570\u636e\u5e93\u7ba1\u7406\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u590d\u5236\u8868\u662f\u5c06\u4e00\u4e2a\u8868\u7684\u7ed3\u6784\u548c\u6570\u636e\u590d\u5236\u5230\u53e6\u4e00\u4e2a\u8868\u4e2d\uff0c\u8fd9\u5bf9\u4e8e\u6570\u636e\u5e93\u5907\u4efd\u3001\u6570\u636e\u8fc1\u79fb\u3001\u6570\u636e\u540c\u6b65\u7b49\u64cd\u4f5c\u975e\u5e38\u6709\u7528\u3002 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35],"tags":[],"class_list":["post-1796","post","type-post","status-publish","format-standard","hentry","category-mysql"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1796","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=1796"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1796\/revisions"}],"predecessor-version":[{"id":1797,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1796\/revisions\/1797"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=1796"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=1796"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=1796"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}