Hey there! Since you're new to PostgreSQL and psql, let's break down exactly how to create a database and insert data using only the psql command line—no extra tools required. I'll keep this straightforward and step-by-step.

First, open your terminal/command prompt and connect to the default PostgreSQL admin database (this is where you'll create your new database). Run this command:

psql -U postgres

• The -U flag specifies the username; postgres is the default superuser account created during installation.
• You'll be prompted for the password you set during PostgreSQL setup (if you enabled password authentication).

Once you're inside the psql shell (you'll see a postgres=# prompt), run this SQL command to create your database. Replace my_first_db with whatever name you want:

CREATE DATABASE my_first_db;

• Don't forget the semicolon at the end—SQL commands in psql require this to execute!
• You'll see a message like CREATE DATABASE if it worked.

Now you need to connect to the database you just created. Use this psql meta-command (note: no semicolon needed here):

\c my_first_db

Your prompt will change to my_first_db=#, confirming you're connected to the right database.

Before inserting data, you need a table to store it in. Let's create a simple example table for users. Run this SQL:

CREATE TABLE users (
    id SERIAL PRIMARY KEY,  -- Auto-incrementing unique ID
    name VARCHAR(50) NOT NULL,  -- User's name (required)
    email VARCHAR(100) UNIQUE NOT NULL  -- Unique email (required)
);

You'll see CREATE TABLE once it's done.

Now you can insert rows of data. Here's how to do it one or multiple records at once:

Insert a single record: #

INSERT INTO users (name, email) VALUES ('Jane Doe', 'jane@example.com');

Insert multiple records at once (more efficient): #

INSERT INTO users (name, email) 
VALUES 
    ('John Smith', 'john@example.com'),
    ('Sarah Lee', 'sarah@example.com');

After running either, you'll get a message like INSERT 0 2 (the number at the end is how many rows were added).

Verify the Data Was Inserted #

To make sure your data is there, run a simple select query:

SELECT * FROM users;

You'll see a table with all the rows you inserted.

If you don't want to go into the psql shell first, you can create a database directly using the createdb system command:

createdb -U postgres my_first_db

Then you can connect to it later with psql -U postgres -d my_first_db.

• To exit the psql shell at any time, type \q and press Enter.
• If you forget a command, type \h for SQL help or \? for psql meta-command help.

内容的提问来源于stack exchange，提问作者dtb