{"id":75874,"date":"2024-10-16T01:57:15","date_gmt":"2024-10-15T17:57:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/75874\/"},"modified":"2024-10-16T01:57:15","modified_gmt":"2024-10-15T17:57:15","slug":"mysql-%e5%ad%98%e5%84%b2%e9%81%8e%e7%a8%8b%e4%b8%ad%e4%bd%bf%e7%94%a8%e6%b8%b8%e6%a8%99%e7%9a%84%e5%af%a6%e4%be%8b","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/75874\/","title":{"rendered":"MySQL \u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528\u6e38\u6a19\u7684\u5be6\u4f8b"},"content":{"rendered":"<h1 id=\"mysql-%e5%ad%98%e5%84%b2%e9%81%8e%e7%a8%8b%e4%b8%ad%e4%bd%bf%e7%94%a8%e6%b8%b8%e6%a8%99%e7%9a%84%e5%af%a6%e4%be%8b-LFJwVxaEYg\">MySQL \u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528\u6e38\u6a19\u7684\u5be6\u4f8b<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMySQL \u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u958b\u6e90\u6578\u64da\u5eab\uff0c\u7279\u5225\u662f\u5728\u7db2\u7d61\u61c9\u7528\u7a0b\u5e8f\u4e2d\u3002\u5b58\u5132\u904e\u7a0b\u662f MySQL \u4e2d\u7684\u4e00\u500b\u91cd\u8981\u7279\u6027\uff0c\u5b83\u5141\u8a31\u7528\u6236\u5c07\u591a\u500b SQL \u8a9e\u53e5\u5c01\u88dd\u5728\u4e00\u8d77\uff0c\u4ee5\u4fbf\u91cd\u8907\u4f7f\u7528\u548c\u7c21\u5316\u8907\u96dc\u7684\u64cd\u4f5c\u3002\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\uff0c\u6e38\u6a19\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u9010\u884c\u8655\u7406\u67e5\u8a62\u7d50\u679c\u96c6\u3002\u672c\u6587\u5c07\u63a2\u8a0e MySQL \u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528\u6e38\u6a19\u7684\u5be6\u4f8b\uff0c\u4e26\u63d0\u4f9b\u76f8\u95dc\u7684\u4ee3\u78bc\u793a\u4f8b\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e6%b8%b8%e6%a8%99%ef%bc%9f-LFJwVxaEYg\">\u4ec0\u9ebc\u662f\u6e38\u6a19\uff1f<\/h2>\n<p>\u6e38\u6a19\u662f\u4e00\u7a2e\u6578\u64da\u5eab\u5c0d\u8c61\uff0c\u7528\u65bc\u5728\u67e5\u8a62\u7d50\u679c\u96c6\u4e2d\u9010\u884c\u8655\u7406\u6578\u64da\u3002\u7576\u67e5\u8a62\u8fd4\u56de\u591a\u884c\u6578\u64da\u6642\uff0c\u6e38\u6a19\u5141\u8a31\u7528\u6236\u9010\u884c\u8a2a\u554f\u9019\u4e9b\u6578\u64da\uff0c\u9019\u5728\u9700\u8981\u5c0d\u6bcf\u4e00\u884c\u9032\u884c\u7279\u5b9a\u64cd\u4f5c\u6642\u7279\u5225\u6709\u7528\u3002<\/p>\n<h2 id=\"%e6%b8%b8%e6%a8%99%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%93%8d%e4%bd%9c-LFJwVxaEYg\">\u6e38\u6a19\u7684\u57fa\u672c\u64cd\u4f5c<\/h2>\n<p>\u5728 MySQL \u4e2d\uff0c\u4f7f\u7528\u6e38\u6a19\u7684\u57fa\u672c\u6b65\u9a5f\u5305\u62ec\uff1a<\/p>\n<ul>\n<li>\u8072\u660e\u6e38\u6a19<\/li>\n<li>\u6253\u958b\u6e38\u6a19<\/li>\n<li>\u63d0\u53d6\u6578\u64da<\/li>\n<li>\u95dc\u9589\u6e38\u6a19<\/li>\n<li>\u91cb\u653e\u6e38\u6a19<\/li>\n<\/ul>\n<h2 id=\"%e5%af%a6%e4%be%8b%ef%bc%9a%e4%bd%bf%e7%94%a8%e6%b8%b8%e6%a8%99%e8%a8%88%e7%ae%97%e6%af%8f%e5%80%8b%e9%83%a8%e9%96%80%e7%9a%84%e5%b9%b3%e5%9d%87%e5%b7%a5%e8%b3%87-LFJwVxaEYg\">\u5be6\u4f8b\uff1a\u4f7f\u7528\u6e38\u6a19\u8a08\u7b97\u6bcf\u500b\u90e8\u9580\u7684\u5e73\u5747\u5de5\u8cc7<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528\u6e38\u6a19\u4f86\u8a08\u7b97\u6bcf\u500b\u90e8\u9580\u7684\u5e73\u5747\u5de5\u8cc7\u3002<\/p>\n<pre><code>DELIMITER \/\/\n\nCREATE PROCEDURE CalculateAverageSalary()\nBEGIN\n    DECLARE done INT DEFAULT FALSE;\n    DECLARE dept_name VARCHAR(255);\n    DECLARE avg_salary DECIMAL(10,2);\n    \n    -- \u8072\u660e\u6e38\u6a19\n    DECLARE dept_cursor CURSOR FOR \n        SELECT department_name FROM departments;\n    \n    -- \u7576\u6e38\u6a19\u7d50\u675f\u6642\uff0c\u8a2d\u7f6e done \u70ba TRUE\n    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;\n\n    -- \u6253\u958b\u6e38\u6a19\n    OPEN dept_cursor;\n\n    read_loop: LOOP\n        -- \u63d0\u53d6\u6578\u64da\n        FETCH dept_cursor INTO dept_name;\n        IF done THEN\n            LEAVE read_loop;\n        END IF;\n\n        -- \u8a08\u7b97\u5e73\u5747\u5de5\u8cc7\n        SELECT AVG(salary) INTO avg_salary \n        FROM employees \n        WHERE department_name = dept_name;\n\n        -- \u8f38\u51fa\u7d50\u679c\n        SELECT dept_name AS Department, avg_salary AS Average_Salary;\n    END LOOP;\n\n    -- \u95dc\u9589\u6e38\u6a19\n    CLOSE dept_cursor;\nEND \/\/\n\nDELIMITER ;<\/code><\/pre>\n<h2 id=\"%e4%bb%a3%e7%a2%bc%e8%a7%a3%e6%9e%90-LFJwVxaEYg\">\u4ee3\u78bc\u89e3\u6790<\/h2>\n<p>\u5728\u4e0a\u8ff0\u4ee3\u78bc\u4e2d\uff0c\u6211\u5011\u9996\u5148\u8072\u660e\u4e86\u4e00\u500b\u6e38\u6a19 <code>dept_cursor<\/code>\uff0c\u7528\u65bc\u9078\u64c7\u6240\u6709\u90e8\u9580\u7684\u540d\u7a31\u3002\u63a5\u8457\uff0c\u6211\u5011\u4f7f\u7528\u4e00\u500b\u5faa\u74b0\u4f86\u9010\u884c\u63d0\u53d6\u90e8\u9580\u540d\u7a31\uff0c\u4e26\u8a08\u7b97\u6bcf\u500b\u90e8\u9580\u7684\u5e73\u5747\u5de5\u8cc7\u3002\u7576\u6e38\u6a19\u904d\u6b77\u5b8c\u6240\u6709\u90e8\u9580\u5f8c\uff0c\u5faa\u74b0\u5c07\u7d50\u675f\uff0c\u4e26\u95dc\u9589\u6e38\u6a19\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8%e6%b8%b8%e6%a8%99%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-LFJwVxaEYg\">\u4f7f\u7528\u6e38\u6a19\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u96d6\u7136\u6e38\u6a19\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u975e\u5e38\u6709\u7528\uff0c\u4f46\u5728\u4f7f\u7528\u6642\u4e5f\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li>\u6027\u80fd\uff1a\u6e38\u6a19\u7684\u6027\u80fd\u901a\u5e38\u4e0d\u5982\u6279\u91cf\u64cd\u4f5c\uff0c\u56e0\u6b64\u61c9\u8b39\u614e\u4f7f\u7528\u3002<\/li>\n<li>\u8cc7\u6e90\u7ba1\u7406\uff1a\u78ba\u4fdd\u5728\u4f7f\u7528\u5b8c\u6e38\u6a19\u5f8c\u95dc\u9589\u548c\u91cb\u653e\u5b83\uff0c\u4ee5\u907f\u514d\u8cc7\u6e90\u6d6a\u8cbb\u3002<\/li>\n<li>\u932f\u8aa4\u8655\u7406\uff1a\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528\u932f\u8aa4\u8655\u7406\u6a5f\u5236\uff0c\u4ee5\u78ba\u4fdd\u5728\u51fa\u73fe\u554f\u984c\u6642\u80fd\u5920\u6b63\u78ba\u8655\u7406\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-LFJwVxaEYg\">\u7e3d\u7d50<\/h2>\n<p>\u5728 MySQL \u4e2d\uff0c\u6e38\u6a19\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\u9010\u884c\u8655\u7406\u6578\u64da\u3002\u901a\u904e\u4e0a\u8ff0\u793a\u4f8b\uff0c\u6211\u5011\u53ef\u4ee5\u770b\u5230\u5982\u4f55\u4f7f\u7528\u6e38\u6a19\u8a08\u7b97\u6bcf\u500b\u90e8\u9580\u7684\u5e73\u5747\u5de5\u8cc7\u3002\u96d6\u7136\u6e38\u6a19\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u975e\u5e38\u6709\u7528\uff0c\u4f46\u5728\u4f7f\u7528\u6642\u4e5f\u9700\u8981\u8003\u616e\u6027\u80fd\u548c\u8cc7\u6e90\u7ba1\u7406\u7b49\u554f\u984c\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u6216\u5176\u4ed6\u6578\u64da\u5eab\u7ba1\u7406\u89e3\u6c7a\u65b9\u6848\u6709\u8208\u8da3\uff0c\u8acb\u96a8\u6642\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u4fe1\u606f\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22 MySQL \u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528\u6e38\u6a19\u7684\u5be6\u4f8b\uff0c\u5b78\u7fd2\u5982\u4f55\u6709\u6548\u5730\u8655\u7406\u67e5\u8a62\u7d50\u679c\u96c6\u4ee5\u63d0\u5347\u6578\u64da\u64cd\u4f5c\u6548\u7387\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-75874","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75874","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=75874"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75874\/revisions"}],"predecessor-version":[{"id":75875,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/75874\/revisions\/75875"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=75874"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=75874"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=75874"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}