IBM i DB2 SQL Tools

JTOpen: The Open Source version of the IBM Toolbox for Java.  Allows for JDBC connection to IBM i

http://jt400.sourceforge.net/

IBM i Access Client Solutions

http://www-03.ibm.com/systems/power/software/i/access/solutions.html

DB2 command line interface 

bash-4.3$ db2util "select * from SCHEMA/TABLE"

https://bitbucket.org/litmis/db2util

Maybe in the future:

https://github.com/coffeeandscripts/sqlcrush

Netbeans via JTOpen

https://netbeans.org/features/ide/database.html