NAME¶
db.select - Selects data from attribute table (performs SQL query
statement(s)).
KEYWORDS¶
database, attribute table, SQL
SYNOPSIS¶
db.select
db.select help
db.select [-
cdvt] [
table=
name]
[
database=
name] [
driver=
name]
[
sql=
string] [
input=
name]
[
fs=
character] [
vs=
character]
[
nv=
string] [
output=
name] [--
verbose]
[--
quiet]
Flags:¶
- -c
-
Do not include column names in output
- -d
-
Describe query only (don't run it)
- -v
-
Vertical output (instead of horizontal)
- -t
-
Only test query, do not execute
- --verbose
-
Verbose module output
- --quiet
-
Quiet module output
Parameters:¶
- table=name
-
Table name
- database=name
-
Database name
Default: $GISDBASE/$LOCATION_NAME/$MAPSET/dbf/
- driver=name
-
Driver name
Options: pg,dbf,ogr,odbc,mysql,sqlite
Default: dbf
- sql=string
-
SQL select statement
For example: 'select * from rybniky where kapri = 'hodne'
- input=name
-
Name of file with sql statement
- fs=character
-
Field separator
Output field separator
Default: |
- vs=character
-
Field separator
Output vertical record separator
- nv=string
-
Null value indicator
- output=name
-
Name for output file (if omitted or "-" output to stdout)
DESCRIPTION¶
db.select prints result of selection from database based on SQL statement
read from input file or from standard input to standard output.
NOTE¶
If parameters for database connection are already set with db.connect, they are
taken as default values and do not need to be spcified each time. Output will
be displayed to stdout or can be directed to a file.
EXAMPLES¶
echo "select * from roads" | db.select
or
cat file.sql | db.select
or
db.select input=file.sql
Select all from table roads
db.select -c driver=odbc database=mydb table=roads \
input=file.sql output=result.csv
Select some string attribute, exclude others:
echo "SELECT * FROM archsites WHERE str1 <> 'No Name'" |
db.select
Select some string attribute with ZERO length:
echo "SELECT * FROM archsites WHERE str1 IS NULL" | db.select
Select coordinates from PostGIS table:
echo "SELECT x(geo),y(geo) FROM localizzazione" | db.select
Count number of cases falling into same position:
When multiple observation have the spatial coordinates, they can still be
counted (if needed, coordinates can be uploaded to the attribute table by
v.to.db:
db.select sql="SELECT long,lat,site_id,department,obs,COUNT(long) as
count_cases \
FROM diseases GROUP BY long,lat"
SEE ALSO¶
GRASS SQL interface,
db.connect, db.describe, db.drivers, db.droptable, db.execute, db.login,
db.tables
AUTHOR¶
Unknown
Modifications: Radim Blazek, ITC-Irst, Trento, Italy
Last changed: $Date: 2013-04-09 18:52:11 +0200 (Tue, 09 Apr 2013) $
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