db.selectgrass - Online in the Cloud

PROGRAM:

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] [vertical_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
For example: ’select * from rybniky where kapri = ’hodne’

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: mysql, odbc, sqlite, pg, ogr, dbf
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 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 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"

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