db.select
Selects data from attribute table.
Performs SQL query statement(s).
db.select [-cdvt] [sql=sql_query] [input=name] [table=name] [driver=name] [database=name] [separator=character] [vertical_separator=character] [null_value=string] [output=name] [--overwrite] [--verbose] [--quiet] [--qq] [--ui]
Example:
db.select
grass.script.run_command("db.select", sql=None, input=None, table=None, driver="sqlite", database="$GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db", separator="pipe", vertical_separator=None, null_value=None, output=None, flags=None, overwrite=False, verbose=False, quiet=False, superquiet=False)
Example:
gs.run_command("db.select")
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
Allowed values: dbf, ogr, 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)
-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
--qq
Very quiet module output
--ui
Force launching GUI dialog
sql : str, optional
SQL SELECT statement
Example: select * from towns where population > 10000
Used as: sql_query
input : str, optional
Name of file containing SQL select statement(s)
'-' for standard input
Used as: input, file, name
table : str, optional
Name of table to query
Used as: input, dbtable, name
driver : str, optional
Name of database driver
Used as: input, dbdriver, name
Allowed values: dbf, ogr, sqlite
Default: sqlite
database : str, optional
Name of database
Used as: input, dbname, name
Default: $GISDBASE/$LOCATION_NAME/$MAPSET/sqlite/sqlite.db
separator : str, optional
Field separator
Special characters: pipe, comma, space, tab, newline
Used as: input, separator, character
Default: pipe
vertical_separator : str, optional
Vertical record separator (requires -v flag)
Special characters: pipe, comma, space, tab, newline
Used as: input, separator, character
null_value : str, optional
String representing NULL value
Used as: string
output : str, optional
Name for output file (if omitted or "-" output to stdout)
Used as: output, file, name
flags : str, optional
Allowed values: c, d, v, t
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: bool, optional
Allow output files to overwrite existing files
Default: False
verbose: bool, optional
Verbose module output
Default: False
quiet: bool, optional
Quiet module output
Default: False
superquiet: bool, optional
Very quiet module output
Default: False
DESCRIPTION
db.select prints result of selection from database based on SQL statement read from input file or from standard input to standard output. Each individual query has to be written on one single line and different 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 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
db.connect, db.describe, db.drivers, db.droptable, db.execute, db.login, db.tables
AUTHORS
Original author unknown (probably CERL)
Modifications by Radim Blazek, ITC-Irst, Trento, Italy
Support for multiple statements by Martin Landa, Czech Technical
University in Prague
SOURCE CODE
Available at: db.select source code
(history)
Latest change: Friday Feb 07 19:16:09 2025 in commit a82a39f