A common mistake people - whose origin isn't Oracle - do: use mixed case and enclose table & column names into double quotes. The fact that you can do that doesn't mean that you should do it. No benefit, many drawbacks.
Any time you reference such a table or a column, you must enclose its name into double quotes and type its name correctly, i.e. not mistype it. For example, "FirstName" would be different from "Firstname" or "FIRSTNAME".
Shortly - get rid of double quotes. Type those names anyway you want - you don't have to pay attention to it. Oracle will store those names in UPPERCASE into the data dictionary, but you'll be able to reference it anyway you want - without using double quotes (firstname, FirstName, FIRSTNAME - all the same).
As of the cause of an error - those tables belong to different users, so you'll have to acquire grant (at least SELECT) from one user to another in order to make it work.
(Not that it matters here, but - those CREATE TABLE statements are invalid, both miss the final close bracket).
A demonstration:
SQL> show user
USER is "SCOTT"
SQL> CREATE TABLE scott."PROPERTY"
2 ( "ItemID" CHAR(36 BYTE) NOT NULL ENABLE,
3 "Name" NVARCHAR2(255) NOT NULL ENABLE,
4 "Type" NVARCHAR2(50),
5 "Value" NCLOB,
6 "Size" NUMBER(*,0),
7 CONSTRAINT "COMPOUNDPK" PRIMARY KEY ("ItemID", "Name"));
Table created.
Connect as user MIKE and create another table:
SQL> connect mike/lion@xe
Connected.
Session altered.
SQL> CREATE TABLE mike."CATALOGITEM"
2 ( "ID" CHAR(36 BYTE) NOT NULL ENABLE,
3 "Type" NUMBER(*,0),
4 "Shortcut" CHAR(1 BYTE),
5 "Name" NVARCHAR2(255),
6 PRIMARY KEY ("ID"));
Table created.
SQL> select *
2 from catalogitem c, property p
3 where p."ItemID" = c."ID";
from catalogitem c, property p
*
ERROR at line 2:
ORA-00942: table or view does not exist
As expected, that doesn't work. Now, back to SCOTT and grant some privileges to MIKE:
SQL> connect scott/tiger@xe
Connected.
Session altered.
SQL> grant select on property to mike;
Grant succeeded.
Back to MIKE:
SQL> connect mike/lion@xe
Connected.
Session altered.
SQL> select *
2 from catalogitem c, scott.property p --> note SCOTT here!
3 where p."ItemID" = c."ID";
no rows selected
SQL>
