Nested Table

Nested table we can create in db level, please check the below example

Steps1:

CREATE TYPE TYPE_NAME AS TABLE OF VARCHAR2(30);

Steps2:

CREATE TABLE nested_tbl (ID NUMBER,col1 type_name)
NESTED TABLE col1 STORE AS colmn1_tab;

Steps3:

SELECT * FROM NESTED_TBL;

Steps4:

begin
INSERT INTO nested_tbl VALUES (1, type_name('A'));
INSERT INTO nested_tbl VALUES (2, type_name('B', 'C'));
INSERT INTO nested_tbl VALUES (3, type_name('D', 'E', 'F'));
COMMIT;
end;

Steps5:

SELECT * FROM nested_tbl;

SELECT id, COLUMN_VALUE FROM nested_tbl t1, TABLE(t1.col1) t2;