## 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=roads \
              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

GRASS SQL interface

db.connect, db.describe, db.drivers, db.droptable, db.execute, db.login, db.tables

## AUTHOR

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

Last changed: $Date$