环境：
os version: window
database version:Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
error:
Tue Jan 19 18:17:06 2016
Exception [type: ACCESS_VIOLATION, UNABLE_TO_READ] [ADDR:0x4] [PC:0x7FC98C8712B, qcdlgcd()+75]
Errors in file D:\APP\ADMINISTRATOR\diag\rdbms\gdwl\gdwl\trace\gdwl_ora_4168.trc  (incident=7441):
ORA-07445: 出现异常错误: 核心转储 [qcdlgcd()+75] [ACCESS_VIOLATION] [ADDR:0x4] [PC:0x7FC98C8712B] [UNABLE_TO_READ] []
Incident details in: D:\APP\ADMINISTRATOR\diag\rdbms\gdwl\gdwl\incident\incdir_7441\gdwl_ora_4168_i7441.trc
Use ADRCI or Support Workbench to package the incident.
See Note 411.1 at My Oracle Support for error and packaging details.




参照文章：
http://stackoverflow.com/questions/26101530/ora-7445-query-causing-oracle-12c-to-crash




his is a bug in 12.1.0.1 (Bug 17633803). It will be fixed in 12.2 and patched in 12.1.0.2.


There is a workaround which is to run


ALTER SESSION SET "_optimizer_unnest_scalar_sq"=false;
I've tried running your sample code above and the workaround does fix the issue in 12.1.0.1


UPDATE


Tested as fixed and working (without the workaround) in 12.1.0.2