v.db.select.1grass - Man Page
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)
Source Code
Available at: v.db.select source code (history)
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