Either u dont have permission to that schema/table OR table does exist. Mostly this issue occurred if you are using other schema tables in your stored procedures. Eg. If you are running Stored Procedure from user/schema ABC and in the same PL/SQL there are tables which is from user/schema XYZ. In this case ABC should have GRANT i.e. privileges of XYZ tables
Grant All On To ABC;
Select * From Dba_Tab_Privs Where Owner = 'XYZ'and Table_Name = <Table_Name>;
There's a strong chance that the privileges to select from table1 have been granted to a role, and the role has been granted to you. Privileges granted to a role are not available to PL/SQL written by a user, even if the user has been granted the role.
You see this a lot for users that have been granted the dba role on objects owned by sys. A user with dba role will be able to, say, SELECT * from V$SESSION, but will not be able to write a function that includes SELECT * FROM V$SESSION.
The fix is to grant explicit permissions on the object in question to the user directly, for example, in the case above, the SYS user has to GRANT SELECT ON V_$SESSION TO MyUser;
A very simple solution is to add the database name with your table name like if your DB name is DBMS and table is info then it will be DBMS.info for any query.
If your query is
select * from STUDENTREC where ROLL_NO=1;
it might show an error but
select * from DBMS.STUDENTREC where ROLL_NO=1;
it doesn't because now actually your table is found.
Make sure the function is in the same DB schema as the table.
Source: Stackoverflow.com