Problems with join (no such attribute, but it exists)

Hi,

I do probably something very silly, but I am total novice in SQL world
(and social scientist, so no CS professional), but I need PostgreSQL
back-end for Grass, so I thought I could try to do some light SELECTing.
Well, I stumbled pretty early:

grass=> \d tracts_towns2000
Table "tracts_towns2000"
Column | Type | Modifiers
-----------+-----------------------+-----------
COMPL_ID | character varying(18) | not null
COUNTY_ID | smallint | not null
TRACT_ID | integer | not null
TOWN_ID | smallint | not null
AREA_ID | smallint | not null
Primary key: tracts_towns2000_pkey

grass=> \d tracts2000
Table "tracts2000"
Column | Type | Modifiers
------------+---------+-----------
objectid | bigint |
area | real |
perimeter | real |
state | text |
county | text |
tract | text |
ct_id | text |
logrecno | text |
blk_count | integer |
total_pop | bigint |
samp_pop | bigint |
dry_pct | real |
dry_acres | real |
dry_sqmi | real |
dry_sqkm | real |
shape_area | text |
shape_len | text |

grass=> SELECT * FROM tracts_towns2000 conv, tracts2000 tr LIMIT 1;
COMPL_ID | COUNTY_ID | TRACT_ID | TOWN_ID | AREA_ID
| objectid | area | perimeter | state | county | tract
| ct_id | logrecno | blk_count | total_pop | samp_pop | dry_pct
| dry_acres | dry_sqmi | dry_sqkm | shape_area
| shape_len
14000US25017341100 | 17 | 341100
| 5 | 5 | 1 | 2.55159e+07 | 45288.6 | 25 | 001
| 010100 | 25001010100 | 0000856 | 137 | 3431 | 3431
| 0.9805 | 6181.92 | 9.659 | 25.017 | 2.55158949367e+007
4.52885899988e+004 |
(1 row)

grass=> SELECT conv.tract_id, tr.tract FROM tracts_towns2000 conv,
tracts2000 tr LIMIT 5;
ERROR: No such attribute or function 'tract_id'

Can anybody explain me, which stupidy I have commited?

Thanks,

Matej Cepl

--
Matej Cepl,
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138 Highland Ave. #10, Somerville, Ma 02143, (617) 623-1488