I believe that this is wrong as (length(varchar(g_0.TIMESTAMPVALUE)) + 1) is obviously greater than length(varchar(g_0.TIMESTAMPVALUE)) which actually causes the exception

DB2 - error getting substring if "from position" is out of range ---------------------------------------------------------------- Key: TEIID-3600 URL: https://issues.jboss.org/browse/TEIID-3600 Project: Teiid Issue Type: Quality Risk Components: Misc. Connectors Reporter: Juraj Duráni Assignee: Steven Hawkins Fix For: 9.1 If second argument of a SUBSTRING(x,y,z) function is out of range of first argument an exception is thrown [1]. Source-specific command [2]. [1] Caused by: com.ibm.db2.jcc.am.SqlDataException: DB2 SQL Error: SQLCODE=-138, SQLSTATE=22011, SQLERRMC=null, DRIVER=4.12.55 at com.ibm.db2.jcc.am.hd.a(hd.java:668) at com.ibm.db2.jcc.am.hd.a(hd.java:60) ... [2] SELECT substr(varchar(g_0.TimestampValue), 40, CASE WHEN 0 > (length(varchar(g_0.TimestampValue)) - (40 - 1)) THEN (length(varchar(g_0.TimestampValue)) - (40 - 1)) ELSE 0 END) FROM SmallA AS g_0 WHERE g_0.IntKey = 1