DB2 for i5/OS V5R4 have no buit-in UPSERT support.

Recently, I need to do UPDATE_or_INSERT (UPSERT) in DB2 for i5/OS V5R4. But, this version DB2 does not have built-in UPSERT function.

In MySQL, I have two ways to implement UPSERT. One is using REPLACE INTO. The other is using ON DUPLICATE KEY UPDATE

It seems that MERGE statement can be used for UPSERT purpose though it is designed for different purpose. But, MERGE statement is not support DB2 v8 for i5/OS V5. It requires 6.1 of the OS.

The following is an article about how to write SQL for both DB2 and MySQL. I bookmark it here as reference: Writing SQL for both MySQL and DB2