Mysql Merge

MySQL MERGE Concept & Alternatives

MySQL MERGE is not directly supported as a single SQL command like in some other database systems (e.g. SQL Server or Oracle), but the concept can be implemented using a combination of INSERT, UPDATE, and DELETE statements.

The MERGE approach is helpful for syncing two tables where data may need to be inserted, updated, or removed depending on conditions. When implemented manually, this requires crafting multiple SQL queries to simulate the behavior.

Users should have SELECT, INSERT, DELETE, and UPDATE privileges on both tables used in the MERGE operation.

🔧 Three Logical Cases in a MERGE Operation

Case 1 – INSERT

If a row exists in the source table but not in the target table, use INSERT to add it to the target.

Case 2 – DELETE

If a row exists in the target table but not in the source, use DELETE to remove it from the target.

Case 3 – UPDATE

If a row exists in both tables and has matching keys but different values in non-key columns, use UPDATE to bring the target in sync with the source.

MySQL Alternatives to MERGE

• INSERT IGNORE – Attempts to insert and silently skips duplicate key violations.
• INSERT ... ON DUPLICATE KEY UPDATE – Inserts new rows or updates existing ones when a key conflict occurs.

✅ Syntax Example

INSERT INTO target_table (id, name)
VALUES (1, 'ravin')
ON DUPLICATE KEY UPDATE
name = VALUES(name);
  

📌 Conclusion

While MERGE is not natively available in MySQL, alternatives like ON DUPLICATE KEY UPDATE and careful use of INSERT IGNORE provide powerful solutions for synchronizing table data efficiently.