alter session
login schema1/schema1 @ db

> create table schema1.test_table (id number(1));

Table created.

> insert into shchema1.test_table values(1);

1 row created;

> commit;

Commit complete;

> grant select on test_table to schema2;

Grant succeeded.

> commit;

Commit complete;


login schema2/schema2 @ db

> select * from schema1.test_table;

ID
---------
1

> select * from test_table;

ERROR at line 1:
ORA-00942: table or view does not exist

> alter session set current_schema = schema1;

Session altered

> select * from test_table;

ID
---------
1