.TH v.db.select 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBv.db.select\fR\fR  \- Prints vector map attributes.
.SH KEYWORDS
vector, attribute table, database, SQL
.SH SYNOPSIS
\fBv.db.select\fR
.br
\fBv.db.select \-\-help\fR
.br
\fBv.db.select\fR [\-\fBrcvf\fR] \fBmap\fR=\fIname\fR  [\fBlayer\fR=\fIstring\fR]   [\fBcolumns\fR=\fIname\fR[,\fIname\fR,...]]   [\fBwhere\fR=\fIsql_query\fR]   [\fBgroup\fR=\fIstring\fR]   [\fBseparator\fR=\fIcharacter\fR]   [\fBvertical_separator\fR=\fIcharacter\fR]   [\fBnull_value\fR=\fIstring\fR]   [\fBfile\fR=\fIname\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-r\fR" 4m
.br
Print minimal region extent of selected vector features instead of attributes
.IP "\fB\-c\fR" 4m
.br
Do not include column names in output
.IP "\fB\-v\fR" 4m
.br
Vertical output (instead of horizontal)
.IP "\fB\-f\fR" 4m
.br
Exclude attributes not linked to features
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBmap\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of vector map
.br
Or data source for direct OGR access
.IP "\fBlayer\fR=\fIstring\fR" 4m
.br
Layer number or name
.br
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.
.br
Default: \fI1\fR
.IP "\fBcolumns\fR=\fIname[,\fIname\fR,...]\fR" 4m
.br
Name of attribute column(s)
.IP "\fBwhere\fR=\fIsql_query\fR" 4m
.br
WHERE conditions of SQL statement without \(cqwhere\(cq keyword
.br
Example: income < 1000 and population >= 10000
.IP "\fBgroup\fR=\fIstring\fR" 4m
.br
GROUP BY conditions of SQL statement without \(cqgroup by\(cq keyword
.IP "\fBseparator\fR=\fIcharacter\fR" 4m
.br
Field separator
.br
Special characters: pipe, comma, space, tab, newline
.br
Default: \fIpipe\fR
.IP "\fBvertical_separator\fR=\fIcharacter\fR" 4m
.br
Output vertical record separator
.br
Special characters: pipe, comma, space, tab, newline
.IP "\fBnull_value\fR=\fIstring\fR" 4m
.br
String representing NULL value
.IP "\fBfile\fR=\fIname\fR" 4m
.br
Name for output file (if omitted or \(dq\-\(dq output to stdout)
.SH DESCRIPTION
\fIv.db.select\fR prints attributes of a vector map from one or several
user selected attribute table columns.
.SH EXAMPLES
All examples are based on the North Carolina sample dataset.
.SS Select and show entire table
.br
.nf
\fC
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
\&...
\fR
.fi
.SS Select and show single column from table
Note: multiple columns can be specified as comma separated list.
.br
.nf
\fC
v.db.select map=roadsmajor column=ROAD_NAME
NC\-50
NC\-50
NC\-98
NC\-50
NC\-98
\&...
\fR
.fi
.SS Print region extent of selected vector features
.br
.nf
\fC
v.db.select \-r map=roadsmajor where=\(dqROAD_NAME = \(cqNC\-98\(cq\(dq
n=248425.389891
s=245640.640081
w=635906.517653
e=661979.801880
\fR
.fi
.SS Select empty vector features (no data entries)
.br
.nf
\fC
v.db.select geonames_wake where=\(dqALTERNATEN IS NULL\(dq
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|...
\&...
\fR
.fi
.SS Select not empty vector features (no data entries)
.br
.nf
\fC
v.db.select geonames_wake where=\(dqALTERNATEN IS NOT NULL\(dq
cat|GEONAMEID|NAME|ASCIINAME|ALTERNATEN|FEATURECLA|FEATURECOD|...
9|4487042|Raleigh|Raleigh|Raleigh,...
31299|4487056|Raleigh\-Durham Airport|Raleigh\-Durham Airport|...
\&...
\fR
.fi
.SS Select features with distinct road names
.br
.nf
\fC
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
\&...
\fR
.fi
It is also possible to combine with \fIwhere\fR option
.br
.nf
\fC
v.db.select map=roadsmajor columns=ROAD_NAME,MULTILANE group=ROAD_NAME where=\(cqROAD_NAME is not null\(cq
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
\fR
.fi
It can also use more columns in \fIgroup\fR option
.br
.nf
\fC
v.db.select map=roadsmajor columns=ROAD_NAME,MULTILANE group=ROAD_NAME,MULTILANE where=\(cqROAD_NAME is not null\(cq
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
\fR
.fi
.SH SEE ALSO
\fI
db.select
\fR
.SH AUTHORS
Radim Blazek, ITC\-Irst, Trento, Italy
.br
Minimal region extent added by Martin Landa,
FBK\-irst (formerly ITC\-irst), Trento, Italy (2008/08)
.br
Group option added by Luca Delucchi,
Fondazione Edmund Mach, Trento, Italy (2015/12)
.SH SOURCE CODE
.PP
Available at: v.db.select source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual