How to enable INMEMORY JOIN GROUP in Oracle 12.2 I have read official Oracle documentation on INMEMORY JOIN GROUP and run code from their tutorials. However I unable to successfully create INMEMORY JOIN GROUP.

Installed database is Oracle 12.2
INMEMORY TABLE and INMEMORY COLUMN were created successfully.

Exception message of INMEMORY JOIN GROUP creation below:
Error starting at line : 1 in command -
CREATE INMEMORY JOIN GROUP employees_departments
    (employees(department_id), departments())
Error report -
ORA-00900: invalid SQL statement
00900. 00000 -  &quot;invalid SQL statement&quot;
*Cause:    
*Action:

My code is
CREATE INMEMORY JOIN GROUP employees_departments
    (employees(department_id), departments());

Are there any Oracle initialize parameters that should be specified in order to turn on support of INMEMORY JOIN GROUP?
Oracle SQL Developer highlights INMEMORY as incorrect syntax:
No you need also a column for the departments table


CREATE TABLE employees(department_id int)


✓




CREATE TAble departments(department_id int)


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CREATE INMEMORY JOIN GROUP employees_departments
    (employees(department_id), departments(department_id));


✓


db&lt;&gt;fiddle here