[GRASS-user] sqlite table join problem "duplicate column name"

[Kirk Wythers]

I am trying to do a 'join' of a column from one table, to the attribute table of another vector. However, I am getting an error about a problem adding another column due to a duplicate column name. 

Snip of commands are below:

GRASS 6.4.1 (latlon):~ > v.info -c ew4kmg
Displaying column types/names for database connection of layer 1:
INTEGER|cat
INTEGER|Id
DOUBLE PRECISION|XMIN
DOUBLE PRECISION|XMAX
DOUBLE PRECISION|YMIN
DOUBLE PRECISION|YMAX

GRASS 6.4.1 (latlon):~ > db.describe -c ew4km_tawc
ncols: 13
nrows: 265090
Column 1: ID:INTEGER:20
Column 2: COUNT:INTEGER:20
Column 3: AREA:DOUBLE PRECISION:20
Column 4: MIN:INTEGER:20
Column 5: MAX:INTEGER:20
Column 6: RANGE:INTEGER:20
Column 7: MEAN:DOUBLE PRECISION:20
Column 8: STD:DOUBLE PRECISION:20
Column 9: SUM:DOUBLE PRECISION:20
Column 10: VARIETY:INTEGER:20
Column 11: MAJORITY:INTEGER:20
Column 12: MINORITY:INTEGER:20
Column 13: MEDIAN:INTEGER:20

GRASS 6.4.1 (latlon):~ > v.db.select ew4kmg | head -7
cat|Id|XMIN|XMAX|YMIN|YMAX
1|128|-1793092|-1789092|-1142894|-1138894
2|129|-1793092|-1789092|-1138894|-1134894
3|130|-1793092|-1789092|-1134894|-1130894
4|826|-1789092|-1785092|-1150894|-1146894
5|827|-1789092|-1785092|-1146894|-1142894
6|828|-1789092|-1785092|-1142894|-1138894

GRASS 6.4.1 (latlon):~ > db.select ew4km_tawc | head -7
ID|COUNT|AREA|MIN|MAX|RANGE|MEAN|STD|SUM|VARIETY|MAJORITY|MINORITY|MEDIAN
127|349|314100|2163|2850|687|2199.68|131.842|767687|36|2163|2185|2163
128|7906|7115400|932|2850|1918|2182.34|534.089|17253600|252|2762|1245|2202
129|10528|9475200|864|2762|1898|1733.46|877.929|18249900|3|864|1568|1568
130|15421|13878900|539|2850|2311|1403.27|806.156|21639900|80|864|539|864
131|17822|16039800|864|2762|1898|1024.77|111.876|18263400|3|1096|2762|1096
132|17689|15920100|864|1096|232|1076.65|64.1395|19044900|2|1096|864|1096

So I am trying to perform the join the MEAN column in the table ew4km_tawc on the Id column in the map ew4kmg. Here is the output:

GRASS 6.4.1 (latlon):~ > v.db.join map=ew4kmg column=Id otable=ew4km_tawc ocolumn=MEAN
DBMI-SQLite driver error:
Error in sqlite3_prepare():
duplicate column name: ID

ERROR: Error while executing: 'ALTER TABLE ew4kmg ADD COLUMN ID INTEGER
       '
ERROR: Cannot continue (problem adding column).
ERROR: Cannot continue.

I am confused since it seems to me, that there has to be a duplicate column name (in this case 'ID', in order for the join to know what to join on… Any suggestions would be much appreciated!

Best,

Kirk