连接是越多越好(主要性能明智)做的事:PostgreSQL的:内对特定值
SELECT u.email, s.id FROM users s, sessions s WHERE u.id = s.user_id AND u.id = 1
或:
SELECT u.email, s.id FROM users s, sessions s WHERE u.id = 1 AND s.user_id = 1
什么:
DELETE FROM users u USING sessions s WHERE u.id = s.user_id AND u.id = 1 AND s.id = 2 RETURNING TRUE;
或者:
DELETE FROM users u USING sessions s WHERE u.id = 1 AND s.user_id = 1 AND s.id = 2 RETURNING TRUE;
表模式:
CREATE EXTENSION "uuid-ossp";
CREATE TABLE users (
id bigserial PRIMARY KEY,
email varchar(254) NOT NULL,
created_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP
);
CREATE UNIQUE INDEX on users (lower(email));
CREATE TABLE sessions (
user_id bigint PRIMARY KEY REFERENCES users ON DELETE CASCADE,
id uuid NOT NULL DEFAULT uuid_generate_v4(),
created_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP
);