GRASS GIS manual: v.db.select

## NAME

v.db.select - Prints vector map attributes.

## KEYWORDS

vector, attribute table, database, SQL

## SYNOPSIS

v.db.select
v.db.select --help
v.db.select [-rcvf] map=name [layer=string] [columns=name[,name,...]] [where=sql_query] [group=string] [separator=character] [vertical_separator=character] [null_value=string] [file=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

### Flags:

-r
  Print minimal region extent of selected vector features instead of attributes
-c
  Do not include column names in output
-v
  Vertical output (instead of horizontal)
-f
  Exclude attributes not linked to features
--overwrite
  Allow output files to overwrite existing files
--help
  Print usage summary
--verbose
  Verbose module output
--quiet
  Quiet module output
--ui
  Force launching GUI dialog

### Parameters:

map=name [required]
  Name of vector map
  Or data source for direct OGR access
layer=string
  Layer number or name
  Vector features can have category values in different layers. This number determines which layer to use. When used with direct OGR access this is the layer name.
  Default: 1
columns=name[,name,...]
  Name of attribute column(s)
where=sql_query
  WHERE conditions of SQL statement without 'where' keyword
  Example: income < 1000 and population >= 10000
group=string
  GROUP BY conditions of SQL statement without 'group by' keyword
separator=character
  Field separator
  Special characters: pipe, comma, space, tab, newline
  Default: pipe
vertical_separator=character
  Output vertical record separator
  Special characters: pipe, comma, space, tab, newline
null_value=string
  String representing NULL value
file=name
  Name for output file (if omitted or "-" output to stdout)

## DESCRIPTION

v.db.select prints attributes of a vector map from one or several user selected attribute table columns.

## EXAMPLES

All examples are based on the North Carolina sample dataset.

### Select and show entire table

    v.db.select map=roadsmajor
    cat|MAJORRDS_|ROAD_NAME|MULTILANE|PROPYEAR|OBJECTID|SHAPE_LEN
    1|1|NC-50|no|0|1|4825.369405
    2|2|NC-50|no|0|2|14392.589058
    3|3|NC-98|no|0|3|3212.981242
    4|4|NC-50|no|0|4|13391.907552
    ...

### Select and show single column from table

Note: multiple columns can be specified as comma separated list.

    v.db.select map=roadsmajor column=ROAD_NAME
    NC-50
    NC-50
    NC-98
    NC-50
    NC-98
    ...

### Print region extent of selected vector features

    v.db.select -r map=roadsmajor where="ROAD_NAME = 'NC-98'"
    n=248425.389891
    s=245640.640081
    w=635906.517653
    e=661979.801880

### Select empty vector features (no data entries)

    v.db.select geonames_wake where="ALTERNATEN IS NULL"
    cat|GEONAMEID|NAME|ASCIINAME|ALTERNATEN|FEATURECLA|FEATURECOD|...
    8|4498303|West Raleigh|West Raleigh||P|PPL|US||NC|338759|123|...
    14|4459467|Cary|Cary||P|PPL|US||NC|103945|146|152|America/Iqaluit|...
    31|4452808|Apex|Apex||P|PPL|US||NC|30873|167|134|America/Iqaluit|...
    ...

### Select not empty vector features (no data entries)

    v.db.select geonames_wake where="ALTERNATEN IS NOT NULL"
    cat|GEONAMEID|NAME|ASCIINAME|ALTERNATEN|FEATURECLA|FEATURECOD|...
    9|4487042|Raleigh|Raleigh|Raleigh,...
    31299|4487056|Raleigh-Durham Airport|Raleigh-Durham Airport|...
    ...

### Select features with distinct road names

    v.db.select map=roadsmajor columns=ROAD_NAME group=ROAD_NAME
    ROAD_NAME

    I-40
    I-440
    I-540
    NC-231
    NC-39
    NC-42
    ...

It is also possible to combine with where option

    v.db.select map=roadsmajor columns=ROAD_NAME,MULTILANE group=ROAD_NAME where='ROAD_NAME is not null'
    ROAD_NAME|MULTILANE
    I-40|yes
    I-440|yes
    I-540|yes
    NC-231|no
    NC-39|no
    NC-42|no
    NC-50|no
    NC-54|no
    NC-55|no
    NC-96|no
    NC-97|no
    NC-98|no
    US-1|
    US-401|no
    US-64|yes
    US-70|yes

It can also use more columns in group option

    v.db.select map=roadsmajor columns=ROAD_NAME,MULTILANE group=ROAD_NAME,MULTILANE where='ROAD_NAME is not null'
    ROAD_NAME|MULTILANE
    I-40|yes
    I-440|yes
    I-540|yes
    NC-231|no
    NC-39|no
    NC-42|no
    NC-50|no
    NC-54|no
    NC-55|no
    NC-96|no
    NC-97|no
    NC-98|no
    US-1|
    US-1|yes
    US-401|no
    US-401|yes
    US-64|yes
    US-70|yes

## SEE ALSO

db.select

## AUTHORS

Radim Blazek, ITC-Irst, Trento, Italy
Minimal region extent added by Martin Landa, FBK-irst (formerly ITC-irst), Trento, Italy (2008/08)
Group option added by Luca Delucchi, Fondazione Edmund Mach, Trento, Italy (2015/12)

Last changed: $Date: 2016-10-27 23:20:55 +0200 (Thu, 27 Oct 2016) $

## SOURCE CODE

Available at: v.db.select source code (history)

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© 2003-2018 GRASS Development Team, GRASS GIS 7.4.2 Reference Manual