PostgreSQL 치트시트

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무료

검색과 인쇄가 가능한 PostgreSQL 참고자료입니다: psql 명령어, JSONB, 배열, CTE, 윈도우 함수, 인덱스, 역할, EXPLAIN까지. 무료입니다.

psql meta-commands

psql -U user -d mydb -h localhost

Connect to a database

\l

List all databases

\c mydb

Switch to another database

\dt

List tables in current schema

\d users

Describe a table (columns, indexes)

\d+ users

Describe with size and storage

\dn

List schemas

\df

List functions

\du

List roles and their attributes

\x

Toggle expanded (vertical) output

\timing

Toggle query execution timing

\e

Edit the query buffer in $EDITOR

\i script.sql

Run SQL from a file

\copy users TO 'users.csv' CSV HEADER

Export a table to CSV

\q

Quit psql

Querying

SELECT * FROM users LIMIT 10;

First 10 rows

WHERE name ILIKE '%ann%'

Case-insensitive pattern match

WHERE name ~* '^a.*z$'

Regex match (case-insensitive)

ORDER BY score DESC NULLS LAST

Control where nulls sort

SELECT DISTINCT ON (user_id) * FROM orders ORDER BY user_id, created_at DESC;

Latest row per group

LIMIT 10 OFFSET 20

Paginate results

FETCH FIRST 5 ROWS ONLY

SQL-standard limit

SELECT ... FOR UPDATE SKIP LOCKED

Queue-style row locking

TABLESAMPLE SYSTEM (1)

Sample ~1% of a table

LATERAL (SELECT ... LIMIT 3)

Per-row correlated subquery

JSONB

data->'user'

Get JSON field (as jsonb)

data->>'name'

Get JSON field as text

data#>>'{user,address,city}'

Get nested value by path as text

data @> '{"active": true}'

Contains: matches subdocument

data ? 'email'

Key exists at top level

data ?| array['a', 'b']

Any of the keys exist

jsonb_set(data, '{name}', '"Sam"')

Update a value by path

data - 'legacy_field'

Delete a key

data || '{"active": true}'

Merge/overwrite fields

jsonb_array_elements(data->'items')

Expand array to rows

jsonb_each(data)

Expand object to key/value rows

jsonb_build_object('id', id, 'name', name)

Build JSON from columns

jsonb_agg(row_to_json(t))

Aggregate rows into a JSON array

jsonb_pretty(data)

Pretty-print for debugging

Arrays & ranges

tags TEXT[]

Declare an array column

ARRAY['a', 'b', 'c']

Array literal

tags[1]

Element access (1-based!)

WHERE 'php' = ANY(tags)

Array contains a value

WHERE tags @> ARRAY['php','sql']

Array contains all values

WHERE tags && ARRAY['php','go']

Arrays overlap (share any)

array_agg(name ORDER BY name)

Aggregate values into an array

unnest(tags)

Expand array to rows

array_length(tags, 1)

Number of elements

string_to_array('a,b', ',')

Split text into an array

period tstzrange

Timestamp range column

WHERE period @> now()

Range contains a value

EXCLUDE USING gist (room WITH =, period WITH &&)

No overlapping bookings

CTEs & window functions

WITH recent AS (SELECT ...) SELECT * FROM recent;

Common table expression

WITH RECURSIVE tree AS (... UNION ALL ...)

Walk hierarchies/graphs

WITH del AS (DELETE ... RETURNING *) INSERT ...

Data-modifying CTE

ROW_NUMBER() OVER (ORDER BY score DESC)

Sequential rank, no ties

RANK() / DENSE_RANK() OVER (...)

Rankings with tie handling

OVER (PARTITION BY user_id ORDER BY at)

Window per group

LAG(price) OVER (ORDER BY day)

Previous row's value

LEAD(price, 2) OVER (...)

Value 2 rows ahead

SUM(amount) OVER (ORDER BY day)

Running total

AVG(x) OVER (ROWS BETWEEN 6 PRECEDING AND CURRENT ROW)

7-row moving average

NTILE(4) OVER (ORDER BY score)

Split rows into quartiles

FIRST_VALUE(name) OVER (...)

First value in the window

Upsert & RETURNING

INSERT ... ON CONFLICT (email) DO UPDATE SET name = EXCLUDED.name;

Upsert on a unique column

ON CONFLICT DO NOTHING

Silently skip duplicates

ON CONFLICT ON CONSTRAINT users_pkey DO UPDATE ...

Target a named constraint

EXCLUDED.column

The value that failed to insert

DO UPDATE ... WHERE users.updated_at < EXCLUDED.updated_at

Conditional upsert

INSERT ... RETURNING id;

Get generated ids back

UPDATE ... RETURNING *;

Return the updated rows

DELETE ... RETURNING id, email;

Return what was deleted

MERGE INTO t USING src ON ... (PG 15+)

SQL-standard merge

Data types

id BIGINT GENERATED ALWAYS AS IDENTITY

Modern auto-increment (prefer)

SERIAL / BIGSERIAL

Legacy auto-increment (sequence)

UUID DEFAULT gen_random_uuid()

Native UUID with generator

TEXT

Unlimited string: no VARCHAR(n) needed

NUMERIC(10, 2)

Exact decimal (money math)

TIMESTAMPTZ

Timestamp with time zone (prefer)

INTERVAL '2 days 3 hours'

Duration type, date arithmetic

BOOLEAN

True/false/null (real type)

JSONB

Binary JSON: indexable, prefer over JSON

BYTEA

Raw binary data

INET / CIDR / MACADDR

Network address types

CREATE TYPE status AS ENUM ('new', 'done');

Custom enum type

col TEXT GENERATED ALWAYS AS (lower(email)) STORED

Generated column

Indexes

CREATE INDEX idx_users_email ON users (email);

Default B-tree index

CREATE UNIQUE INDEX ... ON users (lower(email));

Unique expression index

CREATE INDEX ... ON orders (user_id) WHERE status = 'open';

Partial index

CREATE INDEX ... USING gin (data);

GIN: jsonb/array containment

CREATE INDEX ... USING gin (to_tsvector('english', body));

Full-text search index

CREATE INDEX ... USING gist (location);

GiST: geometry, ranges, KNN

CREATE INDEX ... USING brin (created_at);

BRIN: huge append-only tables

CREATE INDEX CONCURRENTLY ...

Build without locking writes

CREATE INDEX ... ON t (a, b DESC);

Composite with sort direction

CREATE INDEX ... ON t (a) INCLUDE (b);

Covering index (index-only scan)

REINDEX INDEX CONCURRENTLY idx_name;

Rebuild a bloated index

DROP INDEX CONCURRENTLY idx_name;

Remove without blocking

Roles & privileges

CREATE ROLE app LOGIN PASSWORD 'secret';

Create a login role (user)

CREATE ROLE readonly NOLOGIN;

Create a group role

GRANT readonly TO app;

Add a role to a group

GRANT SELECT ON ALL TABLES IN SCHEMA public TO readonly;

Bulk grant reads

ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO readonly;

Auto-grant future tables

GRANT USAGE ON SCHEMA public TO app;

Allow schema access

REVOKE INSERT ON users FROM app;

Remove a privilege

ALTER ROLE app SET statement_timeout = '30s';

Per-role setting

ALTER TABLE users OWNER TO app;

Change object owner

ALTER TABLE docs ENABLE ROW LEVEL SECURITY;

Turn on row-level security

CREATE POLICY own ON docs USING (owner_id = current_user_id());

RLS policy

Maintenance & EXPLAIN

EXPLAIN SELECT ...;

Show the planned query plan

EXPLAIN (ANALYZE, BUFFERS) SELECT ...;

Run it and show real timings

VACUUM (VERBOSE) users;

Reclaim dead-row space

VACUUM FULL users;

Rewrite table (locks it!)

ANALYZE users;

Refresh planner statistics

SELECT * FROM pg_stat_activity;

List running queries

SELECT pg_cancel_backend(pid);

Cancel a running query

SELECT pg_terminate_backend(pid);

Kill a connection

SELECT pg_size_pretty(pg_total_relation_size('users'));

Table size incl. indexes

SELECT pg_size_pretty(pg_database_size('mydb'));

Whole database size

SELECT * FROM pg_stat_user_indexes;

Spot unused indexes

SELECT * FROM pg_locks WHERE NOT granted;

Find blocked lock waits

Backup & restore

pg_dump mydb > mydb.sql

Plain-SQL dump of a database

pg_dump -Fc mydb > mydb.dump

Custom format (compressed)

pg_dump -Fd mydb -j 4 -f dumpdir/

Directory format, 4 parallel jobs

pg_dump -t users -t orders mydb

Dump specific tables only

pg_dump --schema-only mydb

Structure without data

pg_dump --data-only mydb

Data without structure

psql mydb < mydb.sql

Restore a plain-SQL dump

pg_restore -d mydb -j 4 mydb.dump

Restore custom format in parallel

pg_restore -l mydb.dump

List dump contents

pg_restore -t users -d mydb mydb.dump

Restore a single table

pg_dumpall --globals-only > roles.sql

Back up roles and tablespaces

pg_basebackup -D /backup -Fp -Xs -P

Physical base backup (PITR)

Extensions

CREATE EXTENSION IF NOT EXISTS pgcrypto;

Hashing, encryption functions

CREATE EXTENSION "uuid-ossp";

uuid_generate_v4() and friends

CREATE EXTENSION pg_stat_statements;

Track query performance stats

CREATE EXTENSION pg_trgm;

Trigram fuzzy search + LIKE index

CREATE EXTENSION postgis;

Geospatial types and queries

CREATE EXTENSION vector;

pgvector: embeddings & ANN search

CREATE EXTENSION hstore;

Key/value pairs in a column

CREATE EXTENSION postgres_fdw;

Query remote Postgres servers

CREATE EXTENSION citext;

Case-insensitive text type

SELECT * FROM pg_available_extensions;

List installable extensions

\dx

List installed extensions (psql)

“:q”와 일치하는 항목이 없습니다.

PostgreSQL 치트시트 소개

이 PostgreSQL 치트시트는 실제로 자주 입력하는 Postgres 문법을 검색 가능한 한 페이지에 모았습니다: psql 메타 명령어, 쿼리 작성, JSONB, 배열과 range, CTE와 윈도우 함수, upsert와 RETURNING, 데이터 타입, 인덱스, 역할과 권한, 유지보수와 EXPLAIN, 백업과 복원, 그리고 확장 기능까지 다룹니다.

Postgres를 다른 데이터베이스와 다르게 만드는 부분에 초점을 맞춥니다: JSONB 연산자, 배열과 range 타입, RETURNING을 사용한 ON CONFLICT upsert, GIN과 GiST 인덱스, 쿼리가 느릴 때 읽게 되는 EXPLAIN ANALYZE 출력이며, 일상적인 SELECT, JOIN, DDL 문법도 함께 다룹니다.

이 시트는 무료이며 클라이언트 측에서 동작합니다: 검색창으로 실시간으로 행을 필터링하고, 고정된 목차로 섹션을 이동하고, 클릭 한 번으로 문을 복사하고, 책상용 참고자료로 페이지를 인쇄할 수 있습니다.

PostgreSQL 치트시트 사용 방법

psql 메타 명령어와 쿼리 작성부터 인덱스를 거쳐 확장 기능까지 섹션을 훑어보세요.
JSONB, ON CONFLICT, EXPLAIN 같은 키워드를 검색해 모든 행을 실시간으로 필터링하세요.
문법이 아니라 저장이나 성능에 관한 세부 정보가 필요할 때는 데이터 타입이나 인덱스 섹션으로 이동하세요.
문이나 복사 아이콘을 클릭해 SQL을 클립보드에 복사하세요.
오프라인 PostgreSQL 참고자료로 시트를 인쇄하세요.

자주 묻는 질문

12개 섹션입니다: psql 메타 명령어, 쿼리 작성, JSONB, 배열과 range, CTE와 윈도우 함수, upsert와 RETURNING, 데이터 타입, 인덱스, 역할과 권한, 유지보수와 EXPLAIN, 백업과 복원, 확장 기능입니다.

네. 전용 섹션에서 -> 및 ->> 접근자, @> 포함 연산자, jsonb_set, jsonb_array_elements, 그리고 이런 쿼리를 빠르게 만드는 GIN 인덱스를 나열합니다.

시트 맨 앞에 있습니다: \l, \dt, \d, \du, \timing, \x 등 SQL을 작성하기 전에 필요한 백슬래시 메타 명령어들입니다.

네. SQL 스니펫이나 해당 행의 복사 아이콘을 클릭하면 바로 클립보드로 복사됩니다.

네, 완전히 무료입니다: 검색과 인쇄가 가능하며 가입 없이 브라우저에서 렌더링됩니다.

PostgreSQL 치트시트

psql meta-commands

Querying

JSONB

Arrays & ranges

CTEs & window functions

Upsert & RETURNING

Data types

Indexes

Roles & privileges

Maintenance & EXPLAIN

Backup & restore

Extensions

PostgreSQL 치트시트 소개

PostgreSQL 치트시트 사용 방법

자주 묻는 질문

PostgreSQL 치트시트는 무엇을 포함하나요?

JSONB도 다루나요?

psql 명령어도 포함되어 있나요?

클릭 한 번으로 쿼리를 복사할 수 있나요?

PostgreSQL 참고자료는 무료인가요?

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