Access the psql Shell: Open your command prompt or terminal and enter the psql command. You might need to provide the necessary credentials, like username and password, to log in. For example:

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psql -U your_username -d your_database

List of Vital psql Commands: Here are some commonly used psql commands that are vital for working with PostgreSQL from the command line:

• \\l: List all databases.
• \\c database_name: Connect to a specific database.
• \\dt: List all tables in the current database.
• \\du: List all roles (users) in the current database.
• \\q: Quit the psql shell.
• \\?: List available psql commands.
• \\h SQL_COMMAND: Get help for a specific SQL command. For example, \\h SELECT provides information about the SELECT statement.

Sequel Commands

1. SELECT: Used to retrieve data from one or more tables.

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   SELECT column1, column2 FROM table_name WHERE condition;
   
   

2. INSERT: Used to add new records (rows) into a table.

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   INSERT INTO table_name (column1, column2) VALUES (value1, value2);
   

3. UPDATE: Used to modify existing records in a table.

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   UPDATE table_name SET column1 = new_value WHERE condition;
   

4. DELETE: Used to remove records from a table.

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   DELETE FROM table_name WHERE condition;
   

5. CREATE TABLE: Used to create a new table with specified columns and data types.

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   CREATE TABLE table_name (
       column1 data_type,
       column2 data_type,
       ...
   );
   

6. ALTER TABLE: Used to modify an existing table structure (e.g., add, modify, or delete columns).

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   ALTER TABLE table_name
   ADD column_name data_type;
   
   ALTER TABLE table_name
   ALTER COLUMN column_name TYPE new_data_type;
   
   ALTER TABLE table_name
   DROP COLUMN column_name;