Grant Select permission on all tables to another user in Oracle

The following script can be used to grant the select permission on all the tables of the particular schema.

username: which wants to grant permission on the table or owner of the tables.

grantee: which user do you want to give permission

 FOR r IN (
        SELECT owner, table_name 
        FROM all_tables 
        WHERE owner = <username>
    )
    LOOP
        EXECUTE IMMEDIATE 
            'GRANT SELECT ON '||r.owner||'.'||r.table_name||' to ' || <grantee>;
    END LOOP;

Example: 
User Scott want to give select permission to user HR:
 FOR r IN ( 
        SELECT owner, table_name 
        FROM all_tables 
        WHERE owner = 'scott'
    )
    LOOP
        EXECUTE IMMEDIATE 
            'GRANT SELECT ON '||r.owner||'.'||r.table_name||' to ' || HR;
    END LOOP;

you can also use the following script:( you can run this from owner of the tables and only need to replace other user like HR

FOR x IN (SELECT * FROM user_tables)
LOOP   
 EXECUTE IMMEDIATE 'GRANT SELECT ON ' || x.table_name || ' TO <<other user>>'; 
END LOOP;


Example 
User scott want to give select privilest to user HR:
 
sqlplus scott/tiger@orcl
FOR x IN (SELECT * FROM user_tables)
LOOP   
 EXECUTE IMMEDIATE 'GRANT SELECT ON ' || x.table_name || ' TO HR'; 
END LOOP;