Master programming syntax, solve interactive challenges & run live code in Syntaxis Explore Arena →
menu_book Course Curriculum (PostgreSQL Complete Course) expand_more
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
Queries & Joins
LATERAL join FULL OUTER JOIN CROSS JOIN LATERAL FILTER aggregate GROUPING SETS ROLLUP CUBE Window functions Recursive CTE Materialized CTE control
JSON & Arrays
jsonb_extract_path JSONB containment @> jsonb_set jsonb_array_elements jsonb_each Array constructor ANY with arrays Array containment @> unnest() array_agg()
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
EXPLAIN EXPLAIN ANALYZE VACUUM ANALYZE Autovacuum settings pg_stat_activity Statement timeout Connection roles Row-level security Partitioned tables
PostgreSQL Complete Course / Functions & Server Features

MERGE statement

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

12 min read • Advanced

MERGE statement is an atomic PostgreSQL lesson inside Functions & Server Features. 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 MERGE statement rather than on generic PostgreSQL syntax.

Topic-specific example

postgresql-07-09.sql
sql Try It Live 
MERGE INTO inventory i USING shipments s ON i.sku=s.sku WHEN MATCHED THEN UPDATE SET qty=i.qty+s.qty WHEN NOT MATCHED THEN INSERT(sku,qty) VALUES(s.sku,s.qty);
Edge case / engineering note

Test MERGE statement 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

MERGE statement Mastery Check →
← PREVIOUS
Upsert ON CONFLICT
NEXT →
Extensions CREATE EXTENSION