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sqlintermediate

SQL MERGE (Standard Upsert)

Use the SQL MERGE statement for atomic insert-or-update operations with matched/not-matched clauses.

sql
-- PostgreSQL 15+ MERGE syntax
MERGE INTO products AS target
USING staging_products AS source
ON target.sku = source.sku
WHEN MATCHED AND source.price <> target.price THEN
  UPDATE SET
    price = source.price,
    updated_at = NOW()
WHEN NOT MATCHED THEN
  INSERT (sku, name, price, created_at)
  VALUES (source.sku, source.name, source.price, NOW())
WHEN NOT MATCHED BY SOURCE THEN
  UPDATE SET
    is_active = false;

Use Cases

  • Data warehouse loading
  • Syncing external data
  • Incremental updates

Tags

#merge#upsert#etl#data-sync

Related Snippets

Similar patterns you can reuse in the same workflow.

sqlintermediate

SQL Upsert and Merge Patterns

Insert or update records atomically using ON CONFLICT, MERGE, and database-specific upsert syntax.

Best for: Syncing data from external sources

#sql#upsert
sqlintermediate

MERGE / UPSERT Statement

Use MERGE or INSERT ON CONFLICT to upsert rows in a single statement.

Best for: Syncing data from staging tables

#sql#merge
sqlintermediate

UPSERT with ON CONFLICT

Insert or update rows atomically using PostgreSQL ON CONFLICT clause with partial indexes and conditions.

Best for: Sync external data sources

#upsert#postgresql
sqladvanced

ETL Pipeline - Technique 39

Extract Transform Load

Best for: database operations

#sql#database