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示例

本节提供如何使用 SQL 格式化工具处理各种类型 SQL 查询的实用示例。

基本 SELECT 查询

简单 SELECT

输入:

select id, name, email from users where active = 1;

格式化输出:

SELECT
  id,
  name,
  email
FROM users
WHERE active = 1;

带 ORDER BY 的 SELECT

输入:

select u.id, u.name, u.email from users u where u.active = 1 order by u.name asc, u.created_at desc;

格式化输出:

SELECT
  u.id,
  u.name,
  u.email
FROM users u
WHERE u.active = 1
ORDER BY
  u.name ASC,
  u.created_at DESC;

复杂 JOIN 查询

INNER JOIN

输入:

select u.id, u.name, u.email, p.title, p.content from users u inner join posts p on u.id = p.user_id where u.active = 1 and p.published = 1;

格式化输出:

SELECT
  u.id,
  u.name,
  u.email,
  p.title,
  p.content
FROM users u
INNER JOIN posts p ON u.id = p.user_id
WHERE u.active = 1
  AND p.published = 1;

多个 JOIN

输入:

select u.id, u.name, u.email, p.title, p.content, c.name as category_name from users u inner join posts p on u.id = p.user_id left join categories c on p.category_id = c.id where u.active = 1 and p.published = 1;

格式化输出:

SELECT
  u.id,
  u.name,
  u.email,
  p.title,
  p.content,
  c.name AS category_name
FROM users u
INNER JOIN posts p ON u.id = p.user_id
LEFT JOIN categories c ON p.category_id = c.id
WHERE u.active = 1
  AND p.published = 1;

聚合查询

带 GROUP BY 的聚合

输入:

select u.id, u.name, count(p.id) as post_count, sum(p.views) as total_views from users u left join posts p on u.id = p.user_id where u.active = 1 group by u.id, u.name having count(p.id) > 0 order by total_views desc;

格式化输出:

SELECT
  u.id,
  u.name,
  COUNT(p.id) AS post_count,
  SUM(p.views) AS total_views
FROM users u
LEFT JOIN posts p ON u.id = p.user_id
WHERE u.active = 1
GROUP BY
  u.id,
  u.name
HAVING COUNT(p.id) > 0
ORDER BY total_views DESC;

子查询

WHERE 子句中的子查询

输入:

select id, name, email from users where id in (select user_id from posts where published = 1) and active = 1;

格式化输出:

SELECT
  id,
  name,
  email
FROM users
WHERE id IN (
  SELECT user_id
  FROM posts
  WHERE published = 1
)
  AND active = 1;

相关子查询

输入:

select u.id, u.name, u.email, (select count(*) from posts p where p.user_id = u.id and p.published = 1) as post_count from users u where u.active = 1;

格式化输出:

SELECT
  u.id,
  u.name,
  u.email,
  (
    SELECT COUNT(*)
    FROM posts p
    WHERE p.user_id = u.id
      AND p.published = 1
  ) AS post_count
FROM users u
WHERE u.active = 1;

数据修改查询

INSERT 语句

输入:

insert into users (name, email, active, created_at) values ('John Doe', 'john@example.com', 1, now()), ('Jane Smith', 'jane@example.com', 1, now());

格式化输出:

INSERT INTO users (
  name,
  email,
  active,
  created_at
)
VALUES (
  'John Doe',
  'john@example.com',
  1,
  NOW()
), (
  'Jane Smith',
  'jane@example.com',
  1,
  NOW()
);

UPDATE 语句

输入:

update users set name = 'John Updated', email = 'john.updated@example.com', updated_at = now() where id = 1 and active = 1;

格式化输出:

UPDATE users
SET
  name = 'John Updated',
  email = 'john.updated@example.com',
  updated_at = NOW()
WHERE id = 1
  AND active = 1;

DELETE 语句

输入:

delete from posts where user_id in (select id from users where active = 0) and published = 0;

格式化输出:

DELETE FROM posts
WHERE user_id IN (
  SELECT id
  FROM users
  WHERE active = 0
)
  AND published = 0;

数据定义查询

CREATE TABLE

输入:

create table users (id int primary key auto_increment, name varchar(255) not null, email varchar(255) unique not null, active boolean default true, created_at timestamp default current_timestamp, updated_at timestamp default current_timestamp on update current_timestamp);

格式化输出:

CREATE TABLE users (
  id INT PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(255) NOT NULL,
  email VARCHAR(255) UNIQUE NOT NULL,
  active BOOLEAN DEFAULT TRUE,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);

ALTER TABLE

输入:

alter table users add column phone varchar(20), modify column email varchar(320), add index idx_email (email), add constraint fk_user_profile foreign key (id) references user_profiles (user_id);

格式化输出:

ALTER TABLE users
ADD COLUMN phone VARCHAR(20),
MODIFY COLUMN email VARCHAR(320),
ADD INDEX idx_email (email),
ADD CONSTRAINT fk_user_profile FOREIGN KEY (id) REFERENCES user_profiles (user_id);

窗口函数

ROW_NUMBER()

输入:

select id, name, email, row_number() over (partition by department_id order by created_at desc) as row_num from users where active = 1;

格式化输出:

SELECT
  id,
  name,
  email,
  ROW_NUMBER() OVER (
    PARTITION BY department_id
    ORDER BY created_at DESC
  ) AS row_num
FROM users
WHERE active = 1;

公共表表达式 (CTE)

WITH 子句

输入:

with active_users as (select id, name, email from users where active = 1), user_posts as (select user_id, count(*) as post_count from posts where published = 1 group by user_id) select au.id, au.name, au.email, coalesce(up.post_count, 0) as post_count from active_users au left join user_posts up on au.id = up.user_id order by post_count desc;

格式化输出:

WITH active_users AS (
  SELECT
    id,
    name,
    email
  FROM users
  WHERE active = 1
),
user_posts AS (
  SELECT
    user_id,
    COUNT(*) AS post_count
  FROM posts
  WHERE published = 1
  GROUP BY user_id
)
SELECT
  au.id,
  au.name,
  au.email,
  COALESCE(up.post_count, 0) AS post_count
FROM active_users au
LEFT JOIN user_posts up ON au.id = up.user_id
ORDER BY post_count DESC;

格式化选项示例

不同缩进大小

2 个空格:

SELECT
  id,
  name,
  email
FROM users
WHERE active = 1;

4 个空格:

SELECT
    id,
    name,
    email
FROM users
WHERE active = 1;

8 个空格:

SELECT
        id,
        name,
        email
FROM users
WHERE active = 1;

不同关键字大小写

大写:

SELECT
  id,
  name,
  email
FROM users
WHERE active = 1;

小写:

select
  id,
  name,
  email
from users
where active = 1;

保持原样:

Select
  id,
  name,
  email
From users
Where active = 1;

这些示例展示了 SQL 格式化工具的多样性以及它如何处理各种类型的 SQL 查询和不同的格式化首选项。

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