Oracle 12c and Interactive Grid Oracle Apex

To make Interactive Grid work smoothly using auto generate sequence feature of Oracle 12c, remove the Primary Key column or the column on which you have auto generate sequence from SQL query in Interactive Grid.
That's it!

To know how to generate Auto Sequence, click on below link
http://mythass.blogspot.my/2017/11/auto-generate-sequence-in-oracle-12c.html

I hope the above is useful to you.

Auto Generate Sequence in Oracle 12c

Oracle 12c - No need to create sequences.

Use the below highlighted syntax to auto generate Sequences in Oracle 12c.

CREATE TABLE ABC (
    abc_id           NUMBER GENERATED BY DEFAULT AS IDENTITY NOT NULL,
    name             VARCHAR2(50)
)
ALTER TABLE ABC ADD CONSTRAINT abc_id_pk PRIMARY KEY ( abc_id );

Note: In case you are passing the value for primary key manually, Oracle won't generate the sequence for that transaction and will start from the same number where it left last time irrespective of manual insertion.