{"id":2575,"date":"2025-03-09T18:53:47","date_gmt":"2025-03-09T10:53:47","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2575"},"modified":"2025-03-09T18:53:47","modified_gmt":"2025-03-09T10:53:47","slug":"postgresql-%e8%af%ad%e6%b3%95","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/09\/postgresql-%e8%af%ad%e6%b3%95\/","title":{"rendered":"PostgreSQL \u8bed\u6cd5"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\u5b66\u4e60 PostgreSQL \u7684\u8bed\u6cd5\u662f\u638c\u63e1\u6570\u636e\u5e93\u64cd\u4f5c\u7684\u57fa\u7840\uff0c\u63a5\u4e0b\u6765\u6211\u4eec\u53ef\u4ee5\u4ece\u57fa\u672c\u7684 SQL \u8bed\u6cd5\u5165\u624b\uff0c\u9010\u6b65\u6df1\u5165\u4e86\u89e3 PostgreSQL \u7279\u6709\u7684\u529f\u80fd\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>1. \u57fa\u672c\u7684 PostgreSQL SQL \u8bed\u6cd5<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">PostgreSQL \u652f\u6301\u6807\u51c6\u7684 SQL \u8bed\u6cd5\uff0c\u5e76\u63d0\u4f9b\u4e86\u5f88\u591a\u989d\u5916\u7684\u529f\u80fd\u3002\u8ba9\u6211\u4eec\u5148\u6765\u4e86\u89e3\u4e00\u4e9b\u57fa\u7840\u8bed\u6cd5\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1.1 \u521b\u5efa\u6570\u636e\u5e93<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u8981\u521b\u5efa\u4e00\u4e2a\u6570\u636e\u5e93\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>CREATE DATABASE<\/code> \u8bed\u53e5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE DATABASE dbname;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1.2 \u521b\u5efa\u8868<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728 PostgreSQL \u4e2d\uff0c\u521b\u5efa\u8868\u7684\u57fa\u672c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE table_name (\n    column1 datatype &#91;constraint],\n    column2 datatype &#91;constraint],\n    ...\n);<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f8b\u5982\uff0c\u521b\u5efa\u4e00\u4e2a <code>employees<\/code> \u8868\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE employees (\n    employee_id SERIAL PRIMARY KEY,\n    first_name VARCHAR(50),\n    last_name VARCHAR(50),\n    hire_date DATE\n);<\/code><\/pre>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>SERIAL<\/code> \u6570\u636e\u7c7b\u578b\u7528\u4e8e\u81ea\u52a8\u751f\u6210\u552f\u4e00\u7684\u6574\u6570\u503c\uff0c\u5e38\u7528\u4e8e\u4e3b\u952e\u3002<\/li>\n\n\n\n<li><code>PRIMARY KEY<\/code> \u662f\u552f\u4e00\u7ea6\u675f\uff0c\u786e\u4fdd\u8be5\u5217\u7684\u503c\u662f\u552f\u4e00\u7684\u3002<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1.3 \u63d2\u5165\u6570\u636e<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5411\u8868\u4e2d\u63d2\u5165\u6570\u636e\u65f6\uff0c\u4f7f\u7528 <code>INSERT INTO<\/code> \u8bed\u53e5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>INSERT INTO employees (first_name, last_name, hire_date)\nVALUES ('John', 'Doe', '2025-03-10');<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1.4 \u67e5\u8be2\u6570\u636e<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u57fa\u672c\u7684\u67e5\u8be2\u8bed\u6cd5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT column1, column2 FROM table_name;<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f8b\u5982\uff0c\u67e5\u8be2\u6240\u6709\u5458\u5de5\u7684\u540d\u5b57\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT first_name, last_name FROM employees;<\/code><\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\u67e5\u8be2\u6240\u6709\u5217\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT * FROM employees;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1.5 \u66f4\u65b0\u6570\u636e<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u66f4\u65b0\u8868\u4e2d\u7684\u6570\u636e\u4f7f\u7528 <code>UPDATE<\/code> \u8bed\u53e5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>UPDATE employees\nSET first_name = 'Jane'\nWHERE employee_id = 1;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1.6 \u5220\u9664\u6570\u636e<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5220\u9664\u6570\u636e\u7684\u57fa\u672c\u8bed\u6cd5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DELETE FROM employees\nWHERE employee_id = 1;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1.7 \u5220\u9664\u8868<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u4f60\u4e0d\u518d\u9700\u8981\u4e00\u4e2a\u8868\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>DROP TABLE<\/code> \u8bed\u53e5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DROP TABLE employees;<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>2. \u6570\u636e\u7c7b\u578b<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">PostgreSQL \u652f\u6301\u591a\u79cd\u6570\u636e\u7c7b\u578b\uff0c\u5305\u62ec\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u6574\u6570\u7c7b\u578b<\/strong>\uff1a<code>INTEGER<\/code>, <code>BIGINT<\/code><\/li>\n\n\n\n<li><strong>\u6d6e\u52a8\u70b9\u7c7b\u578b<\/strong>\uff1a<code>FLOAT<\/code>, <code>NUMERIC<\/code><\/li>\n\n\n\n<li><strong>\u5b57\u7b26\u7c7b\u578b<\/strong>\uff1a<code>CHAR<\/code>, <code>VARCHAR<\/code>, <code>TEXT<\/code><\/li>\n\n\n\n<li><strong>\u65e5\u671f\u548c\u65f6\u95f4\u7c7b\u578b<\/strong>\uff1a<code>DATE<\/code>, <code>TIME<\/code>, <code>TIMESTAMP<\/code><\/li>\n\n\n\n<li><strong>\u5e03\u5c14\u7c7b\u578b<\/strong>\uff1a<code>BOOLEAN<\/code><\/li>\n\n\n\n<li><strong>\u6570\u7ec4<\/strong>\uff1a<code>INTEGER[]<\/code>\uff08\u652f\u6301\u4e00\u7ef4\u6216\u591a\u7ef4\u6570\u7ec4\uff09<\/li>\n\n\n\n<li><strong>JSON \u7c7b\u578b<\/strong>\uff1a<code>JSON<\/code>, <code>JSONB<\/code>\uff08\u7528\u4e8e\u5b58\u50a8 JSON \u6570\u636e\uff09<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>3. \u5e38\u7528\u64cd\u4f5c\u7b26<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">PostgreSQL \u652f\u6301\u4e30\u5bcc\u7684\u64cd\u4f5c\u7b26\uff0c\u5e38\u89c1\u7684\u6709\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u7b97\u672f\u64cd\u4f5c\u7b26<\/strong>\uff1a<code>+<\/code>, <code>-<\/code>, <code>*<\/code>, <code>\/<\/code><\/li>\n\n\n\n<li><strong>\u6bd4\u8f83\u64cd\u4f5c\u7b26<\/strong>\uff1a<code>=<\/code>, <code>!=<\/code>, <code>><\/code>, <code>&lt;<\/code>, <code>>=<\/code>, <code>&lt;=<\/code><\/li>\n\n\n\n<li><strong>\u903b\u8f91\u64cd\u4f5c\u7b26<\/strong>\uff1a<code>AND<\/code>, <code>OR<\/code>, <code>NOT<\/code><\/li>\n\n\n\n<li><strong>\u5b57\u7b26\u4e32\u64cd\u4f5c\u7b26<\/strong>\uff1a<code>||<\/code>\uff08\u62fc\u63a5\u5b57\u7b26\u4e32\uff09<\/li>\n\n\n\n<li><strong>\u6570\u7ec4\u64cd\u4f5c\u7b26<\/strong>\uff1a<code>@><\/code>\uff08\u6570\u7ec4\u5305\u542b\uff09<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>4. \u805a\u5408\u51fd\u6570<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">PostgreSQL \u63d0\u4f9b\u4e86\u591a\u4e2a\u805a\u5408\u51fd\u6570\u6765\u5904\u7406\u6570\u636e\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>COUNT()<\/code>: \u7edf\u8ba1\u884c\u6570<\/li>\n\n\n\n<li><code>SUM()<\/code>: \u6c42\u548c<\/li>\n\n\n\n<li><code>AVG()<\/code>: \u5e73\u5747\u503c<\/li>\n\n\n\n<li><code>MIN()<\/code> \u548c <code>MAX()<\/code>: \u6700\u5c0f\u503c\u548c\u6700\u5927\u503c<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f8b\u5982\uff0c\u67e5\u8be2\u6240\u6709\u5458\u5de5\u7684\u5e73\u5747\u85aa\u8d44\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT AVG(salary) FROM employees;<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>5. \u8fde\u63a5\u64cd\u4f5c<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">PostgreSQL \u652f\u6301\u591a\u79cd\u8868\u8fde\u63a5\u64cd\u4f5c\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>INNER JOIN<\/strong>\uff1a\u8fd4\u56de\u5339\u914d\u7684\u884c<\/li>\n\n\n\n<li><strong>LEFT JOIN<\/strong>\uff1a\u8fd4\u56de\u5de6\u8868\u6240\u6709\u884c\uff0c\u5373\u4f7f\u53f3\u8868\u6ca1\u6709\u5339\u914d<\/li>\n\n\n\n<li><strong>RIGHT JOIN<\/strong>\uff1a\u8fd4\u56de\u53f3\u8868\u6240\u6709\u884c\uff0c\u5373\u4f7f\u5de6\u8868\u6ca1\u6709\u5339\u914d<\/li>\n\n\n\n<li><strong>FULL JOIN<\/strong>\uff1a\u8fd4\u56de\u5de6\u53f3\u8868\u6240\u6709\u884c\uff0c\u4e0d\u8bba\u662f\u5426\u5339\u914d<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f8b\u5982\uff0c\u67e5\u8be2\u5458\u5de5\u4e0e\u90e8\u95e8\u4fe1\u606f\uff08\u5047\u8bbe\u6709 <code>departments<\/code> \u8868\uff09\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT employees.first_name, employees.last_name, departments.department_name\nFROM employees\nINNER JOIN departments ON employees.department_id = departments.department_id;<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>6. \u5b50\u67e5\u8be2<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">\u5b50\u67e5\u8be2\u662f\u5d4c\u5957\u5728\u5176\u4ed6\u67e5\u8be2\u4e2d\u7684\u67e5\u8be2\uff0c\u7528\u4e8e\u63d0\u4f9b\u6570\u636e\u3002\u4f8b\u5b50\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SELECT first_name, last_name\nFROM employees\nWHERE employee_id IN (SELECT employee_id FROM departments WHERE department_name = 'HR');<\/code><\/pre>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>7. PostgreSQL \u7279\u6709\u7684\u529f\u80fd<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">PostgreSQL \u63d0\u4f9b\u4e86\u8bb8\u591a\u9ad8\u7ea7\u529f\u80fd\uff0c\u4f8b\u5982\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u7a97\u53e3\u51fd\u6570<\/strong>\uff1a\u7528\u4e8e\u5904\u7406\u5206\u7ec4\u6570\u636e\uff0c\u8fdb\u884c\u6392\u540d\u3001\u6c42\u548c\u7b49\u64cd\u4f5c\u3002<\/li>\n\n\n\n<li><strong>CTE\uff08\u516c\u5171\u8868\u8868\u8fbe\u5f0f\uff09<\/strong>\uff1a\u8ba9\u67e5\u8be2\u66f4\u7b80\u6d01\uff0c\u7279\u522b\u662f\u5728\u9700\u8981\u9012\u5f52\u67e5\u8be2\u65f6\u3002<\/li>\n\n\n\n<li><strong>JSON\/JSONB \u7c7b\u578b<\/strong>\uff1a\u9ad8\u6548\u5904\u7406 JSON \u6570\u636e\u3002<\/li>\n\n\n\n<li><strong>\u5168\u6587\u641c\u7d22<\/strong>\uff1a\u652f\u6301\u5168\u6587\u641c\u7d22\u529f\u80fd\uff0c\u9002\u7528\u4e8e\u9700\u8981\u5904\u7406\u5927\u91cf\u6587\u672c\u6570\u636e\u7684\u573a\u666f\u3002<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"wp-block-paragraph\">\u63a5\u4e0b\u6765\u7684\u5b66\u4e60\u53ef\u4ee5\u66f4\u6df1\u5165\u5730\u63a2\u7d22\u8fd9\u4e9b\u529f\u80fd\uff0c\u5e76\u901a\u8fc7\u5b9e\u8df5\u6765\u5de9\u56fa\u8fd9\u4e9b\u8bed\u6cd5\u3002\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\uff01\ud83d\ude0a<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b66\u4e60 PostgreSQL \u7684\u8bed\u6cd5\u662f\u638c\u63e1\u6570\u636e\u5e93\u64cd\u4f5c\u7684\u57fa\u7840\uff0c\u63a5\u4e0b\u6765\u6211\u4eec\u53ef\u4ee5\u4ece\u57fa\u672c\u7684 SQL \u8bed\u6cd5\u5165\u624b\uff0c\u9010\u6b65\u6df1\u5165\u4e86 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":2576,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[78],"tags":[],"class_list":["post-2575","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-postgresql"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2575","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=2575"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2575\/revisions"}],"predecessor-version":[{"id":2577,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2575\/revisions\/2577"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/2576"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2575"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2575"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2575"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}