InterSystems IRIS TSQL Code 8122 Only the first query in a UNION statemen

In this post, you’ll learn about the SQL error code 8122 in InterSystems IRIS database the reason why you are receiving the TSQL message when using the InterSystems IRIS data platform

Error Code :

8122

Reason for the Error code 8122 in InterSystems IRIS DBMS

Only the first query in a UNION statement can have a SELECT with an assignment.