Ściąga PostgreSQL

Bezpłatnie

Przeszukiwalna, drukowalna ściąga PostgreSQL: polecenia psql, JSONB, tablice, CTE, funkcje okna, indeksy, role i EXPLAIN. Za darmo.

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)

Żaden wpis nie pasuje do „:q”.

O Ściąga PostgreSQL

Ta ściąga z PostgreSQL zbiera to, co naprawdę wpisujesz w Postgresie, w jednym źródle z wyszukiwarką: metapolecenia psql, zapytania, JSONB, tablice i zakresy, CTE i funkcje okna, upsert i RETURNING, typy danych, indeksy, role i uprawnienia, konserwację i EXPLAIN, kopie zapasowe i przywracanie oraz rozszerzenia.

Skupia się na tym, co odróżnia Postgresa od innych baz danych: operatorach JSONB, typach tablicowych i zakresowych, upsertach ON CONFLICT z RETURNING, indeksach GIN i GiST oraz wyniku EXPLAIN ANALYZE, który czytasz, gdy zapytanie działa wolno; a jednocześnie obejmuje codzienną składnię SELECT, JOIN i DDL.

Ściąga jest darmowa i działa po stronie klienta: filtruj wiersze na żywo w polu wyszukiwania, przechodź między sekcjami za pomocą przyklejonego spisu treści, kopiuj dowolne polecenie jednym kliknięciem i drukuj stronę jako podręczne źródło informacji.

Jak korzystać z Ściąga PostgreSQL

Przejrzyj sekcje, od Metapoleceń psql i Zapytań, przez Indeksy, aż po Rozszerzenia.
Wyszukaj słowo kluczowe, np. JSONB, ON CONFLICT lub EXPLAIN, aby na żywo przefiltrować każdy wiersz.
Przejdź do Typów danych lub Indeksów, gdy potrzebujesz szczegółów o przechowywaniu i wydajności, a nie składni.
Kliknij polecenie lub ikonę kopiowania, aby skopiować SQL do schowka.
Wydrukuj ściągę, aby mieć papierowe źródło informacji o PostgreSQL.

Najczęściej zadawane pytania

Dwanaście sekcji: metapolecenia psql, zapytania, JSONB, tablice i zakresy, CTE i funkcje okna, upsert i RETURNING, typy danych, indeksy, role i uprawnienia, konserwacja i EXPLAIN, kopie zapasowe i przywracanie oraz rozszerzenia.

Tak. Osobna sekcja wymienia akcesory -> i ->>, operator zawierania @>, jsonb_set, jsonb_array_elements oraz indeks GIN, który przyspiesza te zapytania.

Są na początku ściągi: \l, \dt, \d, \du, \timing, \x i inne metapolecenia z ukośnikiem, których potrzebujesz przed napisaniem jakiegokolwiek SQL.

Tak. Kliknij fragment SQL lub ikonę kopiowania w jego wierszu, a zostanie od razu skopiowany do schowka.

Tak, całkowicie darmowa: z wyszukiwaniem, do druku i wyświetlana w przeglądarce, bez rejestracji.

Popularne wyszukiwania

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