{"id":98,"date":"2026-05-24T19:43:14","date_gmt":"2026-05-24T11:43:14","guid":{"rendered":"https:\/\/zhiyublog.cn\/?p=98"},"modified":"2026-05-24T19:46:17","modified_gmt":"2026-05-24T11:46:17","slug":"%e5%85%b3%e4%ba%8esql%e8%af%ad%e5%8f%a5%e7%9a%84%e7%bb%83%e4%b9%a0","status":"publish","type":"post","link":"https:\/\/zhiyublog.cn\/index.php\/2026\/05\/24\/%e5%85%b3%e4%ba%8esql%e8%af%ad%e5%8f%a5%e7%9a%84%e7%bb%83%e4%b9%a0\/","title":{"rendered":"\u5173\u4e8esql\u8bed\u53e5\u7684\u7ec3\u4e60"},"content":{"rendered":"\n
\"\"<\/div><\/span>
\n

<\/p>\n<\/div><\/div>\n\n\n\n

\u4e00\u3001SQL \u57fa\u7840\u8bed\u6cd5\u6838\u5fc3<\/h2>\n\n\n\n

\u6240\u6709SQL\u8bed\u53e5\u90fd\u9075\u5faa\u4e00\u4e2a\u539f\u5219\uff1a\u5173\u952e\u5b57\u4e0d\u533a\u5206\u5927\u5c0f\u5199\uff0c\u8bed\u53e5\u7ed3\u5c3e\u5fc5\u987b\u52a0\u5206\u53f7 ;<\/strong>\u4e66\u5199\u65f6\u5efa\u8bae\u5173\u952e\u5b57\u5927\u5199\uff0c\u53ef\u8bfb\u6027\u66f4\u5f3a\u3002<\/p>\n\n\n\n

1. \u6570\u636e\u5e93 & \u8868\u57fa\u7840\u64cd\u4f5c\uff08DDL\uff09<\/h3>\n\n\n\n

\u590d\u4e60\u7b2c\u4e00\u6b65\uff1a\u5148\u4f1a\u5efa\u5e93\u3001\u5efa\u8868\u3001\u5220\u5e93\u3001\u5220\u8868\uff0c\u662f\u6240\u6709\u64cd\u4f5c\u7684\u57fa\u7840\u3002<\/p>\n\n\n\n

— \u521b\u5efa\u6570\u636e\u5e93<\/strong><\/p>\n\n\n\n

CREATE DATABASE IF NOT EXISTS test_db;<\/code><\/code><\/pre>\n\n\n\n
— \u4f7f\u7528\u6570\u636e\u5e93<\/strong><\/p>\n\n\n\n
USE test_db;<\/code><\/code><\/pre>\n\n\n\n
— \u5220\u9664\u6570\u636e\u5e93<\/strong><\/p>\n\n\n\n
DROP DATABASE IF EXISTS test_db;<\/code><\/code><\/pre>\n\n\n\n
— \u521b\u5efa\u6570\u636e\u8868\uff08\u6700\u5e38\u7528\u793a\u4f8b\uff1a\u7528\u6237\u8868\uff09<\/strong><\/p>\n\n\n\n
<\/code><\/pre>\n\n\n\n
CREATE TABLE user (\n    id INT PRIMARY KEY AUTO_INCREMENT COMMENT '\u4e3b\u952eID',\n    username VARCHAR(20) NOT NULL COMMENT '\u7528\u6237\u540d',\n    age INT DEFAULT 0 COMMENT '\u5e74\u9f84',\n    create_time DATETIME DEFAULT NOW() COMMENT '\u521b\u5efa\u65f6\u95f4'\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT='\u7528\u6237\u8868';<\/code><\/pre>\n\n\n\n
— \u5220\u9664\u8868<\/strong><\/p>\n\n\n\n
DROP TABLE IF EXISTS user;<\/code><\/code><\/pre>\n\n\n\n
2. \u6570\u636e\u589e\u5220\u6539\uff08DML\uff09<\/h3>\n\n\n\n
— \u65b0\u589e\u6570\u636e INSERT<\/strong><\/p>\n\n\n\n
INSERT INTO user(username,age) VALUES ('\u5f20\u4e09',20),('\u674e\u56db',22);<\/code><\/pre>\n\n\n\n
— \u4fee\u6539\u6570\u636e UPDATE\uff08\u5fc5\u987b\u52a0WHERE\uff0c\u5426\u5219\u6539\u5168\u8868\uff09<\/strong><\/p>\n\n\n\n
UPDATE user SET age=21 WHERE username='\u5f20\u4e09';<\/code><\/pre>\n\n\n\n
— \u5220\u9664\u6570\u636e DELETE\uff08\u5fc5\u987b\u52a0WHERE\uff0c\u5426\u5219\u5220\u5168\u8868\uff09<\/strong><\/p>\n\n\n\n
DELETE FROM user WHERE username='\u674e\u56db';<\/code><\/pre>\n\n\n\n
\n\n\n\n
\u4e8c\u3001DQL \u67e5\u8be2\u8bed\u6cd5<\/h2>\n\n\n\n
\u67e5\u8be2\u662fSQL\u7684\u7075\u9b42<\/strong>\uff0c\u65e0\u8bba\u662f\u5f00\u53d1\u67e5\u6570\u636e\u3001\u6570\u636e\u5206\u6790\u7edf\u8ba1\uff0c90%\u7684\u5de5\u4f5c\u90fd\u662f\u5199\u67e5\u8be2\u8bed\u53e5\u3002<\/p>\n\n\n\n
1. \u57fa\u7840\u67e5\u8be2\u8bed\u6cd5\u7ed3\u6784\uff08\u56fa\u5b9a\u987a\u5e8f\uff0c\u5fc5\u987b\u7262\u8bb0\uff09<\/h3>\n\n\n\n
\u5b8c\u6574\u67e5\u8be2\u8bed\u53e5\u6267\u884c\u987a\u5e8f\uff1a<\/p>\n\n\n\n
SELECT \u5b57\u6bb5 FROM \u8868\u540d WHERE \u6761\u4ef6 GROUP BY \u5206\u7ec4 HAVING \u5206\u7ec4\u6761\u4ef6 ORDER BY \u6392\u5e8f LIMIT \u5206\u9875<\/code><\/p>\n\n\n\n
2. \u5e38\u7528\u57fa\u7840\u67e5\u8be2<\/h3>\n\n\n\n
— \u67e5\u8be2\u6240\u6709\u5b57\u6bb5<\/strong><\/p>\n\n\n\n
SELECT * FROM user;<\/code><\/code><\/pre>\n\n\n\n
— \u67e5\u8be2\u6307\u5b9a\u5b57\u6bb5<\/strong><\/p>\n\n\n\n
SELECT id,username,age FROM user;<\/code><\/code><\/pre>\n\n\n\n
— \u522b\u540d\u67e5\u8be2 AS\uff08\u53ef\u7701\u7565\uff09<\/strong><\/p>\n\n\n\n
SELECT username AS \u59d3\u540d,age \u5e74\u9f84 FROM user;<\/code><\/code><\/pre>\n\n\n\n
— \u53bb\u91cd\u67e5\u8be2 DISTINCT<\/strong><\/p>\n\n\n\n
SELECT DISTINCT age FROM user;<\/code><\/code><\/pre>\n\n\n\n
3. \u6761\u4ef6\u67e5\u8be2 WHERE\uff08\u6838\u5fc3\u7b5b\u9009\uff09<\/h3>\n\n\n\n
\u5e38\u7528\u8fd0\u7b97\u7b26\uff1a>\u3001<\u3001=\u3001!=\u3001>=\u3001<=<\/code>\u3001BETWEEN AND<\/code>\u3001IN<\/code>\u3001LIKE<\/code>\u3001IS NULL<\/code><\/p>\n\n\n\n
-- \u67e5\u8be2\u5e74\u9f8420\u5c81\u7684\u7528\u6237\nSELECT * FROM user WHERE age=20;\n\n-- \u67e5\u8be2\u5e74\u9f8418-22\u5c81\u7684\u7528\u6237\nSELECT * FROM user WHERE age BETWEEN 18 AND 22;\n\n-- \u67e5\u8be2\u6307\u5b9a\u591a\u4e2a\u7528\u6237\nSELECT * FROM user WHERE username IN ('\u5f20\u4e09','\u738b\u4e94');\n\n-- \u6a21\u7cca\u67e5\u8be2\uff08%\u5339\u914d\u4efb\u610f\u5b57\u7b26\uff09\nSELECT * FROM user WHERE username LIKE '\u5f20%';\n\n-- \u67e5\u8be2\u5e74\u9f84\u4e3a\u7a7a\u7684\u6570\u636e\nSELECT * FROM user WHERE age IS NULL;<\/code><\/pre>\n\n\n\n
4. \u6392\u5e8f & \u5206\u9875<\/h3>\n\n\n\n
-- \u5347\u5e8f\u6392\u5e8f ASC\uff08\u9ed8\u8ba4\uff09\uff0c\u964d\u5e8f DESC\nSELECT * FROM user ORDER BY age DESC;\n\n-- \u5206\u9875 LIMIT \u8d77\u59cb\u4e0b\u6807,\u6761\u6570\n-- \u67e5\u8be2\u524d2\u6761\u6570\u636e\nSELECT * FROM user LIMIT 0,2;<\/code><\/pre>\n\n\n\n
5. \u805a\u5408\u51fd\u6570 + \u5206\u7ec4\u67e5\u8be2\uff08\u6570\u636e\u5206\u6790\u5fc5\u5907\uff09<\/h3>\n\n\n\n
\u5e38\u7528\u805a\u5408\u51fd\u6570\uff1aCOUNT<\/code>\u7edf\u8ba1\u3001SUM<\/code>\u6c42\u548c\u3001AVG<\/code>\u5e73\u5747\u503c\u3001MAX<\/code>\u6700\u5927\u503c\u3001MIN<\/code>\u6700\u5c0f\u503c<\/p>\n\n\n\n
-- \u7edf\u8ba1\u603b\u4eba\u6570\nSELECT COUNT(*) FROM user;\n\n-- \u7edf\u8ba1\u5e73\u5747\u5e74\u9f84\nSELECT AVG(age) FROM user;\n\n-- \u6309\u5e74\u9f84\u5206\u7ec4\uff0c\u7edf\u8ba1\u6bcf\u4e2a\u5e74\u9f84\u7684\u4eba\u6570\nSELECT age,COUNT(*) AS \u4eba\u6570 FROM user GROUP BY age;\n\n-- \u5206\u7ec4\u540e\u7b5b\u9009\uff08HAVING \u914d\u5408 GROUP BY\uff09\n-- \u7b5b\u9009\u4eba\u6570\u5927\u4e8e1\u7684\u5e74\u9f84\u7ec4\nSELECT age,COUNT(*) AS \u4eba\u6570 FROM user GROUP BY age HAVING \u4eba\u6570 > 1;<\/code><\/pre>\n\n\n\n
\n
\u91cd\u70b9\u533a\u5206<\/strong>\uff1aWHERE<\/code> \u662f\u5206\u7ec4\u524d\u7b5b\u9009\u6570\u636e\uff0cHAVING<\/code> \u662f\u5206\u7ec4\u540e\u7b5b\u9009\u7ed3\u679c<\/p>\n<\/blockquote>\n\n\n\n
\n\n\n\n
\u4e09\u3001\u591a\u8868\u8054\u67e5<\/h2>\n\n\n\n
\u5b9e\u9645\u4e1a\u52a1\u4e2d\uff0c\u6570\u636e\u4e0d\u4f1a\u5b58\u5728\u4e00\u5f20\u8868\u91cc\uff0c\u591a\u8868\u8054\u67e5\u662f\u5fc5\u987b\u638c\u63e1\u7684\u6838\u5fc3\u6280\u80fd\u3002<\/p>\n\n\n\n
1. \u8054\u67e5\u56db\u79cd\u7c7b\u578b<\/h3>\n\n\n\n
    \n
  • INNER JOIN \u5185\u8fde\u63a5<\/strong>\uff1a\u53ea\u67e5\u8be2\u4e24\u8868\u5339\u914d\u7684\u6570\u636e\uff08\u4ea4\u96c6\uff09<\/li>\n\n\n\n
  • LEFT JOIN \u5de6\u8fde\u63a5<\/strong>\uff1a\u4ee5\u5de6\u8868\u4e3a\u4e3b\uff0c\u5de6\u8868\u6570\u636e\u5168\u90e8\u5c55\u793a\uff0c\u53f3\u8868\u65e0\u6570\u636e\u663e\u793anull\uff08\u6700\u5e38\u7528\uff09<\/li>\n\n\n\n
  • RIGHT JOIN \u53f3\u8fde\u63a5<\/strong>\uff1a\u4ee5\u53f3\u8868\u4e3a\u4e3b<\/li>\n\n\n\n
  • FULL JOIN \u5168\u8fde\u63a5<\/strong>\uff1a\u5c55\u793a\u4e24\u8868\u6240\u6709\u6570\u636e\uff08MySQL\u4e0d\u652f\u6301\uff0c\u53ef union \u66ff\u4ee3\uff0c\u5373\u8054\u5408\uff09<\/li>\n<\/ul>\n\n\n\n
    2. \u5b9e\u6218\u793a\u4f8b\uff08\u5de6\u8fde\u63a5\uff09<\/h3>\n\n\n\n
    \u5047\u8bbe\u5b58\u5728\u7528\u6237\u8868 user\u3001\u8ba2\u5355\u8868 order\uff0c\u901a\u8fc7\u7528\u6237id\u5173\u8054<\/p>\n\n\n\n
    -- \u67e5\u8be2\u6240\u6709\u7528\u6237\u53ca\u5bf9\u5e94\u7684\u8ba2\u5355\u4fe1\u606f\uff08\u65e0\u8ba2\u5355\u7528\u6237\u4e5f\u5c55\u793a\uff09\nSELECT u.username,o.order_id,o.order_time\nFROM user u\nLEFT JOIN `order` o ON u.id = o.user_id;<\/code><\/pre>\n\n\n\n
    \u5f85\u7eed\u2014\u2014<\/h2>\n","protected":false},"excerpt":{"rendered":"
    \u4e00\u3001SQL \u57fa\u7840\u8bed\u6cd5\u6838\u5fc3 \u6240\u6709SQL\u8bed\u53e5\u90fd\u9075\u5faa\u4e00\u4e2a\u539f\u5219\uff1a\u5173\u952e\u5b57\u4e0d\u533a\u5206\u5927\u5c0f\u5199\uff0c\u8bed\u53e5\u7ed3\u5c3e\u5fc5\u987b\u52a0\u5206\u53f7 ;\u4e66\u5199\u65f6\u5efa\u8bae\u5173 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[9,3],"tags":[],"class_list":["post-98","post","type-post","status-publish","format-standard","hentry","category-coding","category-passage"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/posts\/98","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/comments?post=98"}],"version-history":[{"count":3,"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/posts\/98\/revisions"}],"predecessor-version":[{"id":102,"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/posts\/98\/revisions\/102"}],"wp:attachment":[{"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/media?parent=98"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/categories?post=98"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zhiyublog.cn\/index.php\/wp-json\/wp\/v2\/tags?post=98"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}