db.select(1grass) GRASS GIS User's Manual db.select(1grass)
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] [sql=sql_query] [input=name] [table=name]
[driver=name] [database=name] [separator=character] [verti-
cal_separator=character] [null_value=string] [output=name]
[--overwrite] [--help] [--verbose] [--quiet] [--ui]
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
--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:
sql=sql_query
SQL SELECT statement
Example: select * from towns where population > 10000
input=name
Name of file containing SQL select statement(s)
’-’ for standard input
table=name
Name of table to query
driver=name
Name of database driver
Options: dbf, mysql, odbc, ogr, pg, sqlite
Default: sqlite
database=name
Name of database
Default: $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db
separator=character
Field separator
Special characters: pipe, comma, space, tab, newline
Default: pipe
vertical_separator=character
Vertical record separator (requires -v flag)
Special characters: pipe, comma, space, tab, newline
null_value=string
String representing NULL value
output=name
Name for output file (if omitted or "-" output to stdout)
DESCRIPTION
db.select prints result of selection from database based on SQL state-
ment read from input file or from standard input to standard output.
Each individual query has to be written on one single line and differ-
ent queries have to be written on separate lines.
NOTE
If parameters for database connection are already set with db.connect,
they are taken as default values and do not need to be specified each
time. Output will be displayed to standard output or can be directed to
a file (option output).
EXAMPLES
Basic usage
db.select sql="select * from roads"
or
echo "select * from roads" | db.select input=-
or
db.select input=file.sql
or
cat file.sql | db.select input=-
Select all from table roads:
db.select -c driver=odbc database=mydb table=hospitals \
input=file.sql output=result.csv
Select some string attribute, exclude others:
db.select sql="SELECT * FROM archsites WHERE str1 <> ’No Name’"
Select some string attribute with ZERO length:
db.select sql="SELECT * FROM archsites WHERE str1 IS NULL"
Select coordinates from PostGIS table:
db.select sql="SELECT x(geo),y(geo) FROM localizzazione"
Execute multiple SQL statements
cat file.sql
SELECT * FROM busstopsall WHERE cat = 1
SELECT cat FROM busstopsall WHERE cat > 4 AND cat < 8
db.select input=file.sql
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 ta-
ble 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
db.connect, db.describe, db.drivers, db.droptable, db.execute, db.lo-
gin, db.tables
GRASS SQL interface
AUTHORS
Original author unknown (probably CERL)
Modifications by Radim Blazek, ITC-Irst, Trento, Italy
Support for multiple statements by Martin Landa, Czech Technical Uni-
versity in Prague
SOURCE CODE
Available at: db.select source code (history)
Accessed: unknown
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GRASS 7.8.7 db.select(1grass)
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