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Core PostgreSQL
SERIAL and identity columns RETURNING ILIKE DISTINCT ON LIMIT OFFSET VALUES table constructor Type casts :: Dollar-quoted strings Search path Temporary tables
Data Types
UUID JSONB Arrays Range types INET and CIDR NUMERIC precision TIMESTAMPTZ INTERVAL ENUM type Composite type
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JSON & Arrays
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Indexes
B-tree index Hash index GIN index GiST index BRIN index Partial index Expression index Covering INCLUDE index Concurrent index creation Index-only scan concept
Transactions & Locking
Transaction isolation SAVEPOINT SELECT FOR UPDATE SELECT FOR SHARE Advisory locks Deadlock example Serializable retry Deferrable constraints Two-phase commit SKIP LOCKED
Functions & Server Features
SQL function PL/pgSQL function DO block Trigger function Generated columns LISTEN and NOTIFY COPY command Upsert ON CONFLICT MERGE statement Extensions CREATE EXTENSION
Administration & Performance
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PostgreSQL Complete Course / Indexes

Hash index

Learn Hash index in PostgreSQL through the exact construct, a dedicated example, a boundary case, and a mastery check.

12 min read • Intermediate

Hash index is an atomic PostgreSQL lesson inside Indexes. The example uses the specific syntax, command, API, instruction, or language rule named by this lesson.

Study the construct itself, then change one relevant input and predict the result before running it. That keeps this lesson focused on Hash index rather than on generic PostgreSQL syntax.

Topic-specific example

postgresql-05-02.sql
sql Try It Live 
CREATE INDEX idx_tokens_hash ON tokens USING hash(token);
Edge case / engineering note

Test Hash index with an empty result, NULL/missing value, duplicate key, or concurrent operation where relevant; database behavior should be verified at the boundary shown by this example.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

Hash index Mastery Check →
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