Extracting data where a column is max

Hi All,

I have the following data:
IPADB=# SELECT * FROM inventory.tbl_data;
inventory_id | item_id | quantity
--------------+------------+----------
1 | RMFPB14BK | 551
1 | RPP3S114BK | 629
1 | RPP3S14YL | 1009
1 | TW360PYSD | 444
1 | TW360PYWH | 910
6 | 004173-1 | 44
6 | RMFPB14BK | 399
6 | RPP3S14YL | 1233
9 | RPP3S14YL | 50
(9 rows)

I want to retrieve the item_id and the quantity corresponding to the maximum
inventory_id. I can get the proper item_id.
IPADB=# SELECT max(inventory.tbl_data.inventory_id) AS inventory_id,
inventory.tbl_data.item_id FROM inventory.tbl_data GROUP BY
inventory.tbl_data.item_id ORDER BY inventory_id, inventory.tbl_data.item_id;
inventory_id | item_id
--------------+------------
1 | RPP3S114BK
1 | TW360PYSD
1 | TW360PYWH
6 | 004173-1
6 | RMFPB14BK
9 | RPP3S14YL
(6 rows)

But how do I get the corresponding quantity for each record?

TIA

BTW The SQL code to create the table and data is below. (Are ya proud of me
Michael? ;-) )

Kind Regards,
Keith

--
-- PostgreSQL database dump
--

--
-- Name: inventory; Type: SCHEMA; Schema: -; Owner: postgres
--

CREATE SCHEMA inventory;

--
-- Name: tbl_data; Type: TABLE; Schema: inventory; Owner: postgres
--

CREATE TABLE tbl_data (
inventory_id integer NOT NULL,
item_id character varying(20) NOT NULL,
quantity real NOT NULL
);

--
-- Name: tbl_data; Type: TABLE DATA; Schema: inventory; Owner: postgres
--

INSERT INTO tbl_data VALUES (1, 'RMFPB14BK', 551);
INSERT INTO tbl_data VALUES (1, 'RPP3S114BK', 629);
INSERT INTO tbl_data VALUES (1, 'RPP3S14YL', 1009);
INSERT INTO tbl_data VALUES (1, 'TW360PYSD', 444);
INSERT INTO tbl_data VALUES (1, 'TW360PYWH', 910);
INSERT INTO tbl_data VALUES (6, '004173-1', 44);
INSERT INTO tbl_data VALUES (6, 'RMFPB14BK', 399);
INSERT INTO tbl_data VALUES (6, 'RPP3S14YL', 1233);
INSERT INTO tbl_data VALUES (9, 'RPP3S14YL', 50);

--
-- Name: tbl_data_pkey; Type: CONSTRAINT; Schema: inventory; Owner: postgres
--

ALTER TABLE ONLY tbl_data
ADD CONSTRAINT tbl_data_pkey PRIMARY KEY (inventory_id, item_id);

--
-- Name: TABLE tbl_data; Type: COMMENT; Schema: inventory; Owner: postgres
--

COMMENT ON TABLE tbl_data IS 'Contains the total count data.';

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