PostgreSQL Cheat Sheet

Show current date YYYY-MM-DD

SELECT current\_date;

Calculate age between two dates

SELECT age(timestamp, timestamp);

Show current time with time zone

SELECT current\_time;

Make dates using integers

SELECT make_date(2021,03,25);

List schemas

\dn
SELECT schema_name FROM information_schema.schemata;
SELECT nspname FROM pg_catalog.pg_namespace;

Create schema

CREATE SCHEMA IF NOT EXISTS <schema_name>;

Drop schema

DROP SCHEMA IF EXISTS <schema_name> CASCADE;

List roles

SELECT rolname FROM pg_roles;

Create user

CREATE USER <user_name> WITH PASSWORD '<password>';

Drop user

DROP USER IF EXISTS <user_name>;

Alter user password

ALTER ROLE <user_name> WITH PASSWORD '<password>';

Select all data

SELECT \* FROM <table_name>;

Read one row of data

SELECT \* FROM <table_name> LIMIT 1;

Search for data

SELECT \* FROM <table_name> WHERE <column_name> = <value>;

Insert data

INSERT INTO <table_name> VALUES( <value_1>, <value_2> );

Update data

UPDATE <table_name>
SET <column_1> = <value_1>, <column_2> = <value_2>
WHERE <column_1> = <value>;

Delete all data

DELETE FROM <table_name>;

Delete specific data

DELETE FROM <table_name>
WHERE <column_name> = <value>;

Add column

ALTER TABLE <table_name> IF EXISTS
ADD <column_name> <data_type> [<constraints>];

Update column

ALTER TABLE <table_name> IF EXISTS
ALTER <column_name> TYPE <data_type> [<constraints>];

Delete column

ALTER TABLE <table_name> IF EXISTS
DROP <column_name>;

Update column to be an auto-incrementing primary key

ALTER TABLE <table_name>
ADD COLUMN <column_name> SERIAL PRIMARY KEY;

Insert into a table, with an auto-incrementing primary key

INSERT INTO <table_name>
VALUES (DEFAULT, <value1>);
INSERT INTO <table_name> (<column1_name>,<column2_name>)
VALUES ( <value1>,<value2> );

Become the postgres user, if you have permission errors

sudo su - postgres
psql

Grant all permissions on database

GRANT ALL PRIVILEGES ON DATABASE <db_name> TO <user_name>;

Grant connection permissions on database

GRANT CONNECT ON DATABASE <db_name> TO <user_name>;

Grant permissions on schema

GRANT USAGE ON SCHEMA public TO <user_name>;

Grant permissions to functions

GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA public TO <user_name>;

Grant permissions to select, update, insert, delete, on a all tables

GRANT SELECT, UPDATE, INSERT ON ALL TABLES IN SCHEMA public TO <user_name>;

Grant permissions, on a table

GRANT SELECT, UPDATE, INSERT ON <table_name> TO <user_name>;

Grant permissions, to select, on a table

GRANT SELECT ON ALL TABLES IN SCHEMA public TO <user_name>;

List tables, in current db

\dt
SELECT table_schema,table_name FROM information_schema.tables ORDER BY table_schema,table_name;

List tables, globally

\dt \*.\*.
SELECT \* FROM pg_catalog.pg_tables

List table schema

\d <table_name>
\d+ <table_name>
SELECT column_name, data_type, character_maximum_length
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = '<table\_name>';

Create table

CREATE TABLE <table_name>(
  <column_name> <column_type>,
  <column_name> <column_type>
);

Create table, with an auto-incrementing primary key

CREATE TABLE <table_name> (
  <column_name> SERIAL PRIMARY KEY
);

Delete table

DROP TABLE IF EXISTS <table_name> CASCADE;

List databases

\l

Connect to database

\c <database_name>

Show current database

SELECT current_database();

Create database

CREATE DATABASE <database_name> WITH OWNER <username>;

Drop database

DROP DATABASE IF EXISTS <database_name>;

Rename database

ALTER DATABASE <old_name> RENAME TO <new_name>;

Show version

SHOW SERVER_VERSION;

Show system status

\conninfo

Show environmental variables

SHOW ALL;

List users

SELECT rolname FROM pg_roles;

Show current user

SELECT current\_user;

Show current user's permissions

\du

Show current database

SELECT current_database();

Show all tables in database

\dt

List functions

\df <schema>