SQL> desc patient;
Name Null? Type
----------------------------------------- -------- ----------------------------
P_ID NOT NULL NUMBER
MRN NUMBER
NAME VARCHAR2(30)
ADMITTED_BY NUMBER
REFFERED_BY NUMBER
CCID NUMBER
R_ID NUMBER
BED_NUM NUMBER

SQL> desc item;
Name Null? Type
----------------------------------------- -------- ----------------------------
ITEM_NUM NOT NULL NUMBER
UNIT_COST NUMBER(38)
DESCRIPTION VARCHAR2(20)

SQL> desc items_used;
Name Null? Type
----------------------------------------- -------- ----------------------------
I_ID NOT NULL NUMBER
PATIENT_ID NOT NULL NUMBER
DATE_USED NOT NULL DATE
TIME_USED NOT NULL VARCHAR2(8)
QUANTITY NUMBER
TOTAL_COST NUMBER(38)



query is asking me to give a patients name, and a description of the items they used where their mrn is equal to a certain value. cannot figure out how to only give these two pieces of information given these three tables.

patient id is foreign key to p_id in patient. i_id is a foreign key of item_num in item. any help would be greately appreciated.

It would make it easier to assist you if you posted the CREATE TABLE statements for 3 tables.
Also INSERT statements for sample data test SQL SELECT against.

Create table Patient
(
P_ID number primary key,
MRN number,
Name varchar2(30),
Admitted_By references Physician(PH_ID),
Reffered_By references physician(PH_ID),
CCID number,
R_ID number,
Bed_num number,
constraint fk_tblpatient foreign key(CCID,R_ID,Bed_num) references Bed( CCID,Room_num,bed_num)
);

Create table item
(
Item_Num number primary key,
Unit_Cost decimal,
description varchar2(20)
);

create table Items_Used
(
I_ID references item(Item_Num),
Patient_ID references Patient(P_ID),
Date_used Date,
Time_used varchar2(8),
quantity number,
total_cost decimal,
PRIMARY KEY(I_ID,Patient_ID,Date_used,Time_used)
);

insert into Patient
values
('200','55671','Michel','101','106','1','113','01' );

insert into Item
values
('1000','5.00','Needles');

insert into Items_Used
values
('1000','203','14-JUL-11','8:30','3','30.00');

thanx. i added an additional where clause to choose only a paticular patient based on mrn, since my teacher was working with joins, was there any way possible to do this with joins?

>was there any way possible to do this with joins?
yes, but you need to contribute something to this exercise.

and what do i need to contribute?

>and what do i need to contribute?
valid syntax for the JOINs

well i tried doing something in class like this:

select name,description from patient p,item i inner join items_used on i.item_num=items_used.id inner join items_used on p.P_ID=Items_used.patient_ID where mrn='55671';

but that gave me a syntax error. i didnt really study joins to well yet and this is an introductory course.

fix the syntax error

I thought that we didn't hand an answer to homework without seeing what they already tried and give hints, not the solution.