advanced features

文件信息

📄 原文件：03_advanced_features.sql
🔤 语言：SQL

SQL 脚本

sql

-- ============================================================
--                    PostgreSQL 高级特性
-- ============================================================
-- 本文件介绍 PostgreSQL 的高级特性。
-- ============================================================

-- \c learn_postgresql

-- ============================================================
--                    1. JSON/JSONB 操作
-- ============================================================

/*
JSON vs JSONB:
- JSON: 存储原始文本，保留格式和顺序
- JSONB: 二进制格式，更高效，支持索引
- 推荐使用 JSONB
*/

-- 创建包含 JSONB 的表
CREATE TABLE IF NOT EXISTS products (
    id SERIAL PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    category VARCHAR(50),
    price NUMERIC(10, 2),
    attributes JSONB DEFAULT '{}',
    tags JSONB DEFAULT '[]',
    created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
);

-- 插入 JSON 数据
INSERT INTO products (name, category, price, attributes, tags) VALUES
    ('iPhone 15', 'phone', 5999.00,
     '{"brand": "Apple", "storage": "128GB", "color": "黑色", "specs": {"screen": "6.1寸", "chip": "A16"}}',
     '["5G", "iOS", "旗舰"]'),
    ('MacBook Pro', 'laptop', 14999.00,
     '{"brand": "Apple", "storage": "512GB", "ram": "16GB", "specs": {"screen": "14寸", "chip": "M3"}}',
     '["macOS", "专业", "创意"]'),
    ('Galaxy S24', 'phone', 4999.00,
     '{"brand": "Samsung", "storage": "256GB", "color": "白色", "specs": {"screen": "6.2寸", "chip": "骁龙8"}}',
     '["5G", "Android", "旗舰"]');

-- --- JSON 操作符 ---

-- -> 获取 JSON 对象（返回 JSON）
SELECT name, attributes -> 'brand' AS brand_json FROM products;

-- ->> 获取 JSON 文本（返回 TEXT）
SELECT name, attributes ->> 'brand' AS brand FROM products;

-- 嵌套访问
SELECT name, attributes -> 'specs' ->> 'screen' AS screen FROM products;

-- #> 路径访问（返回 JSON）
SELECT name, attributes #> '{specs, chip}' AS chip FROM products;

-- #>> 路径访问（返回 TEXT）
SELECT name, attributes #>> '{specs, chip}' AS chip FROM products;

-- --- JSONB 特有操作符 ---

-- @> 包含
SELECT name FROM products WHERE attributes @> '{"brand": "Apple"}';

-- <@ 被包含
SELECT name FROM products WHERE '{"brand": "Apple"}' <@ attributes;

-- ? 存在键
SELECT name FROM products WHERE attributes ? 'color';

-- ?| 存在任意键
SELECT name FROM products WHERE attributes ?| array['color', 'ram'];

-- ?& 存在所有键
SELECT name FROM products WHERE attributes ?& array['brand', 'storage'];

-- || 合并
SELECT name, attributes || '{"warranty": "1年"}' AS updated FROM products;

-- - 删除键
SELECT name, attributes - 'color' AS without_color FROM products;

-- #- 删除路径
SELECT name, attributes #- '{specs, chip}' AS without_chip FROM products;

-- --- JSONB 函数 ---

-- jsonb_set 设置值
SELECT name, jsonb_set(attributes, '{color}', '"红色"') AS updated FROM products;

-- jsonb_insert 插入值
SELECT name, jsonb_insert(tags, '{0}', '"新品"') AS updated FROM products;

-- jsonb_each 展开为行
SELECT name, key, value
FROM products, jsonb_each(attributes)
WHERE category = 'phone';

-- jsonb_array_elements 展开数组
SELECT name, tag
FROM products, jsonb_array_elements_text(tags) AS tag;

-- jsonb_object_keys 获取所有键
SELECT DISTINCT key
FROM products, jsonb_object_keys(attributes) AS key;

-- jsonb_typeof 获取类型
SELECT name, jsonb_typeof(attributes), jsonb_typeof(tags) FROM products;

-- jsonb_agg 聚合为 JSON 数组
SELECT category, jsonb_agg(name) AS products FROM products GROUP BY category;

-- jsonb_object_agg 聚合为 JSON 对象
SELECT jsonb_object_agg(name, price) AS price_map FROM products;

-- --- JSONB 索引 ---
CREATE INDEX idx_products_attributes ON products USING GIN (attributes);
CREATE INDEX idx_products_tags ON products USING GIN (tags);

-- 针对特定路径的索引
CREATE INDEX idx_products_brand ON products ((attributes ->> 'brand'));


-- ============================================================
--                    2. 数组操作
-- ============================================================

-- 创建包含数组的表
CREATE TABLE IF NOT EXISTS articles (
    id SERIAL PRIMARY KEY,
    title VARCHAR(200) NOT NULL,
    tags TEXT[],
    scores INTEGER[],
    created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
);

INSERT INTO articles (title, tags, scores) VALUES
    ('PostgreSQL 入门', ARRAY['数据库', 'SQL', 'PostgreSQL'], ARRAY[95, 88, 92]),
    ('Python 数据分析', ARRAY['Python', '数据分析', 'Pandas'], ARRAY[90, 85, 88]),
    ('Web 开发指南', ARRAY['Web', 'JavaScript', 'React'], ARRAY[88, 92, 90]);

-- --- 数组操作符 ---

-- = 相等
SELECT * FROM articles WHERE tags = ARRAY['数据库', 'SQL', 'PostgreSQL'];

-- @> 包含
SELECT * FROM articles WHERE tags @> ARRAY['Python'];

-- <@ 被包含
SELECT * FROM articles WHERE ARRAY['数据库'] <@ tags;

-- && 有交集
SELECT * FROM articles WHERE tags && ARRAY['Python', 'SQL'];

-- || 连接
SELECT title, tags || ARRAY['推荐'] AS new_tags FROM articles;

-- 索引访问（从1开始）
SELECT title, tags[1] AS first_tag, scores[1] AS first_score FROM articles;

-- 切片
SELECT title, tags[1:2] AS first_two_tags FROM articles;

-- --- 数组函数 ---

-- array_length 长度
SELECT title, array_length(tags, 1) AS tag_count FROM articles;

-- array_dims 维度
SELECT title, array_dims(tags) FROM articles;

-- array_position 查找位置
SELECT title, array_position(tags, 'Python') AS python_pos FROM articles;

-- array_remove 删除元素
SELECT title, array_remove(tags, 'SQL') AS without_sql FROM articles;

-- array_replace 替换元素
SELECT title, array_replace(tags, 'SQL', 'MySQL') AS replaced FROM articles;

-- array_cat 连接数组
SELECT title, array_cat(tags, ARRAY['新标签']) AS extended FROM articles;

-- array_append / array_prepend
SELECT title, array_append(tags, '热门') AS appended FROM articles;
SELECT title, array_prepend('精选', tags) AS prepended FROM articles;

-- unnest 展开数组
SELECT title, unnest(tags) AS tag FROM articles;

-- 使用 unnest 统计标签
SELECT tag, COUNT(*) AS count
FROM articles, unnest(tags) AS tag
GROUP BY tag
ORDER BY count DESC;

-- array_agg 聚合为数组
SELECT array_agg(title) AS all_titles FROM articles;

-- --- 数组与聚合 ---

-- 计算平均分
SELECT title, (SELECT AVG(s) FROM unnest(scores) AS s) AS avg_score FROM articles;

-- ANY / ALL
SELECT * FROM articles WHERE 90 = ANY(scores);
SELECT * FROM articles WHERE 80 < ALL(scores);


-- ============================================================
--                    3. 全文搜索
-- ============================================================

-- 创建文章内容表
CREATE TABLE IF NOT EXISTS posts (
    id SERIAL PRIMARY KEY,
    title VARCHAR(200) NOT NULL,
    content TEXT,
    search_vector TSVECTOR,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
);

INSERT INTO posts (title, content) VALUES
    ('PostgreSQL 全文搜索', 'PostgreSQL 提供了强大的全文搜索功能，支持中文分词和多种搜索模式。'),
    ('数据库索引优化', '合理使用索引可以显著提升数据库查询性能，包括 B-tree、GIN、GiST 等索引类型。'),
    ('SQL 查询技巧', '掌握 SQL 查询技巧可以写出高效的数据库查询语句，提高开发效率。');

-- 更新搜索向量
UPDATE posts SET search_vector = to_tsvector('simple', title || ' ' || content);

-- 创建全文搜索索引
CREATE INDEX idx_posts_search ON posts USING GIN (search_vector);

-- --- 全文搜索查询 ---

-- 基本搜索
SELECT title FROM posts
WHERE search_vector @@ to_tsquery('simple', 'PostgreSQL');

-- 使用 plainto_tsquery（自动处理空格）
SELECT title FROM posts
WHERE search_vector @@ plainto_tsquery('simple', '数据库 索引');

-- 使用 phraseto_tsquery（短语搜索）
SELECT title FROM posts
WHERE search_vector @@ phraseto_tsquery('simple', '全文搜索');

-- 布尔操作
SELECT title FROM posts
WHERE search_vector @@ to_tsquery('simple', 'PostgreSQL | SQL');  -- OR

SELECT title FROM posts
WHERE search_vector @@ to_tsquery('simple', '数据库 & 索引');  -- AND

SELECT title FROM posts
WHERE search_vector @@ to_tsquery('simple', 'SQL & !PostgreSQL');  -- NOT

-- --- 搜索排名 ---

-- ts_rank 计算相关度
SELECT
    title,
    ts_rank(search_vector, to_tsquery('simple', '数据库')) AS rank
FROM posts
WHERE search_vector @@ to_tsquery('simple', '数据库')
ORDER BY rank DESC;

-- ts_headline 高亮显示
SELECT
    title,
    ts_headline('simple', content, to_tsquery('simple', '索引'),
        'StartSel=<b>, StopSel=</b>') AS highlighted
FROM posts
WHERE search_vector @@ to_tsquery('simple', '索引');


-- ============================================================
--                    4. 范围类型
-- ============================================================

-- PostgreSQL 支持范围类型
CREATE TABLE IF NOT EXISTS events (
    id SERIAL PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    during TSTZRANGE,  -- 时间戳范围
    capacity INT4RANGE  -- 整数范围
);

INSERT INTO events (name, during, capacity) VALUES
    ('会议A', '[2024-01-15 09:00, 2024-01-15 12:00)', '[10, 50)'),
    ('会议B', '[2024-01-15 14:00, 2024-01-15 17:00)', '[20, 100)'),
    ('会议C', '[2024-01-15 10:00, 2024-01-15 11:00)', '[5, 30)');

-- 范围操作符
-- @> 包含元素
SELECT * FROM events WHERE during @> '2024-01-15 10:30'::TIMESTAMPTZ;

-- && 重叠
SELECT * FROM events
WHERE during && '[2024-01-15 11:00, 2024-01-15 15:00)'::TSTZRANGE;

-- << 完全在左边
SELECT * FROM events
WHERE during << '[2024-01-15 13:00, 2024-01-15 14:00)'::TSTZRANGE;

-- 范围函数
SELECT
    name,
    lower(during) AS start_time,
    upper(during) AS end_time,
    upper(during) - lower(during) AS duration
FROM events;

-- 排除约束（防止时间重叠）
ALTER TABLE events
ADD CONSTRAINT no_overlap EXCLUDE USING GIST (during WITH &&);


-- ============================================================
--                    5. 继承
-- ============================================================

-- 父表
CREATE TABLE IF NOT EXISTS vehicles (
    id SERIAL PRIMARY KEY,
    brand VARCHAR(50) NOT NULL,
    model VARCHAR(50) NOT NULL,
    year INTEGER
);

-- 子表继承父表
CREATE TABLE IF NOT EXISTS cars (
    doors INTEGER,
    fuel_type VARCHAR(20)
) INHERITS (vehicles);

CREATE TABLE IF NOT EXISTS motorcycles (
    engine_cc INTEGER
) INHERITS (vehicles);

-- 插入数据
INSERT INTO cars (brand, model, year, doors, fuel_type)
VALUES ('Toyota', 'Camry', 2023, 4, 'hybrid');

INSERT INTO motorcycles (brand, model, year, engine_cc)
VALUES ('Honda', 'CBR', 2023, 650);

-- 查询所有车辆（包括子表）
SELECT * FROM vehicles;

-- 只查询父表
SELECT * FROM ONLY vehicles;

-- 查询特定子表
SELECT * FROM cars;
SELECT * FROM motorcycles;


-- ============================================================
--                    6. 存储过程与函数
-- ============================================================

-- --- 创建函数 ---

-- 返回标量值
CREATE OR REPLACE FUNCTION get_employee_count(dept_id INTEGER)
RETURNS INTEGER AS $$
DECLARE
    emp_count INTEGER;
BEGIN
    SELECT COUNT(*) INTO emp_count
    FROM employees
    WHERE department_id = dept_id;
    RETURN emp_count;
END;
$$ LANGUAGE plpgsql;

-- 调用函数
SELECT get_employee_count(1);

-- 返回表
CREATE OR REPLACE FUNCTION get_employees_by_dept(dept_id INTEGER)
RETURNS TABLE(id INTEGER, name VARCHAR, salary NUMERIC) AS $$
BEGIN
    RETURN QUERY
    SELECT e.id, e.name, e.salary
    FROM employees e
    WHERE e.department_id = dept_id
    ORDER BY e.salary DESC;
END;
$$ LANGUAGE plpgsql;

-- 调用
SELECT * FROM get_employees_by_dept(1);

-- 返回 SETOF
CREATE OR REPLACE FUNCTION get_high_salary_employees(min_salary NUMERIC)
RETURNS SETOF employees AS $$
BEGIN
    RETURN QUERY
    SELECT * FROM employees WHERE salary >= min_salary;
END;
$$ LANGUAGE plpgsql;

-- --- 存储过程 (PostgreSQL 11+) ---
CREATE OR REPLACE PROCEDURE transfer_money(
    from_account VARCHAR,
    to_account VARCHAR,
    amount NUMERIC
)
LANGUAGE plpgsql
AS $$
BEGIN
    -- 扣款
    UPDATE users SET balance = balance - amount WHERE username = from_account;

    -- 存款
    UPDATE users SET balance = balance + amount WHERE username = to_account;

    -- 自动提交（过程中可以使用事务控制）
    COMMIT;
END;
$$;

-- 调用存储过程
CALL transfer_money('alice', 'bob', 100);

-- --- 触发器 ---

-- 创建更新时间触发器函数
CREATE OR REPLACE FUNCTION update_modified_column()
RETURNS TRIGGER AS $$
BEGIN
    NEW.updated_at = CURRENT_TIMESTAMP;
    RETURN NEW;
END;
$$ LANGUAGE plpgsql;

-- 创建触发器
CREATE TRIGGER trigger_users_updated
    BEFORE UPDATE ON users
    FOR EACH ROW
    EXECUTE FUNCTION update_modified_column();


-- ============================================================
--                    7. 视图
-- ============================================================

-- 普通视图
CREATE OR REPLACE VIEW employee_details AS
SELECT
    e.id,
    e.name,
    e.email,
    e.salary,
    d.name AS department,
    m.name AS manager
FROM employees e
LEFT JOIN departments d ON e.department_id = d.id
LEFT JOIN employees m ON e.manager_id = m.id;

-- 查询视图
SELECT * FROM employee_details;

-- 物化视图（缓存结果）
CREATE MATERIALIZED VIEW department_stats AS
SELECT
    d.id,
    d.name,
    COUNT(e.id) AS employee_count,
    ROUND(AVG(e.salary), 2) AS avg_salary,
    SUM(e.salary) AS total_salary
FROM departments d
LEFT JOIN employees e ON d.id = e.department_id
GROUP BY d.id, d.name
WITH DATA;

-- 查询物化视图
SELECT * FROM department_stats;

-- 刷新物化视图
REFRESH MATERIALIZED VIEW department_stats;

-- 并发刷新（需要唯一索引）
CREATE UNIQUE INDEX ON department_stats (id);
REFRESH MATERIALIZED VIEW CONCURRENTLY department_stats;


-- ============================================================
--                    8. 扩展
-- ============================================================

-- 查看已安装扩展
SELECT * FROM pg_extension;

-- 查看可用扩展
SELECT * FROM pg_available_extensions WHERE name LIKE '%uuid%';

-- 安装扩展
CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
CREATE EXTENSION IF NOT EXISTS "pgcrypto";

-- 使用 UUID
SELECT uuid_generate_v4();

-- 使用加密
SELECT crypt('password', gen_salt('bf'));

-- 验证密码
SELECT crypt('password', '$2a$06$...') = '$2a$06$...';


-- ============================================================
--                    总结
-- ============================================================

/*
PostgreSQL 高级特性：

JSONB：
- 操作符：->, ->>, #>, @>, ?, ||
- 函数：jsonb_set, jsonb_each, jsonb_agg
- GIN 索引支持

数组：
- 操作符：@>, <@, &&, ||
- 函数：array_agg, unnest, array_length
- ANY/ALL 比较

全文搜索：
- TSVECTOR 和 TSQUERY
- GIN 索引
- ts_rank 排名
- ts_headline 高亮

范围类型：
- INT4RANGE, TSTZRANGE 等
- 重叠和包含操作
- 排除约束

继承：
- 表继承
- ONLY 关键字

函数与过程：
- CREATE FUNCTION
- CREATE PROCEDURE
- 触发器

视图：
- 普通视图
- 物化视图 (MATERIALIZED VIEW)
- REFRESH MATERIALIZED VIEW

扩展：
- uuid-ossp
- pgcrypto
- 众多社区扩展
*/

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561

advanced features ​

SQL 脚本 ​

💬 讨论

advanced features

SQL 脚本