I have a table like this
Table "public.zone_polygons"
Column | Type |
-----------+-------------------------+
id | integer |
zone_id | integer |
zone_name | text |
zone_path | text |
geom | geometry(Geometry,4326) |
Each zone_path has a list of lat longs as text in this format
75.2323 30.7423,
75.3432 30.5344,
75.5423 30.2342,
75.9123 30.3122,
75.2323 30.7423
I am trying to generate a geometry using the zone_path values using the below query.
update zone_polygons set geom=ST_SetSRID(ST_MakePolygon(ST_GeomFromText('LINESTRING(zone_path)')), 4326);
I get the below error
ERROR: parse error - invalid geometry
HINT: "LINESTRING(zo" <-- parse error at position 13 within geometry
Is there a way in postgis to use one of the fields to create geometry.
I believe you have a typo and the coordinates are in Long - Lat (India), not Lat-Long (middle of Barents sea). PostGIS expects coordinates as Long - Lat, so if the input list is indeed in lat-long, it would needs to be swapped. You can either fix the source or use ST_FlipCoordinates
Since the coordinates are saved in a column, you would need to concatenate the LINESTRING( and the column content (not name) using 'LINESTRING(' || zone_path || ')'
with src as (select '75.2323 30.7423, 75.3432 30.5344, 75.5423 30.2342, 75.9123 30.3122, 75.2323 30.7423' zone_path)
SELECT ST_ASTEXT(
ST_SetSRID(
ST_MakePolygon(
ST_GeomFromText('LINESTRING(' || zone_path || ')')), 4326))
FROM src;
--> POLYGON((75.2323 30.7423,75.3432 30.5344,75.5423 30.2342,75.9123 30.3122,75.2323 30.7423))
Related
I have a source table, which lists like below:
public.source
Id | part_no | category
1 | 01270-4 | Landscape
2 | 01102-3 | Sports
Then, I have target table with jsonb column (combinations) , which list like below;
public.target
Id | part_no | combinations
7 | 01270-4 | {"subject":""}
8 | 01102-3 | {"subject":""}
My problem is - how I can update the target table with jsonb column (combinations) with the values coming from source table using the part_no column?
Output like:
Id | part_no | combinations
7 | 01270-4 | {"subject":"Landscape"}
8 | 01102-3 | {"subject":"Sports"}
I tried below but giving error:
UPDATE public.target t
SET combinations = jsonb_set(combinations,'{subject}','s.category',false)
FROM public.source s
WHERE s.part_no = t.part_no;
ERROR: invalid input syntax for type json
LINE 2: SET combinations = jsonb_set(combinations,'{subject}', 's.categor...
^
DETAIL: Token "s" is invalid.
CONTEXT: JSON data, line 1: s...
SQL state: 22P02
Character: 77
You should use to_jsonb function to convert s.category to JSON
Demo
UPDATE public.target t
SET combinations = jsonb_set(combinations,'{subject}',to_jsonb(s.category),false)
FROM public.source s
WHERE s.part_no = t.part_no
Or you can use sample structure for join and update two JSON field:
Demo
UPDATE public.target t
SET combinations = combinations || jsonb_build_object('subject', s.category)
FROM public.source s
WHERE s.part_no = t.part_no
I have this query
WITH buffered AS (
SELECT
ST_Buffer(geom , 10, 'endcap=round join=round') AS geom,
id
FROM line),
hexagons AS (
SELECT
ST_HexagonGrid(10, buffered.geom) AS hex,
buffered.id
FROM buffered
) SELECT * FROM hexagons;
This gives the datatype record in the column hex. This is unexpected. I expect geometry as a datatype. Why is that?
According to the documentation, the function ST_HexagonGrid returns a setof record. These records contain however a geometry attribute called geom, so in order to access the geometry of this record you have to wrap the variable with parenthesis () and call the attribute with a dot ., e.g.
SELECT (hex).geom FROM hexagons;
or just access fetch all attributes using * (in this case, i,j and geom):
SELECT (hex).* FROM hexagons;
Demo (PostGIS 3.1):
WITH j (hex) AS (
SELECT
ST_HexagonGrid(
10,ST_Buffer('LINESTRING(-105.55 41.11,-115.48 37.16,-109.29 29.38,-98.34 27.13)',1))
)
SELECT ST_AsText((hex).geom,2) FROM j;
st_astext
----------------------------------------------------------------------------------------
POLYGON((-130 34.64,-125 25.98,-115 25.98,-110 34.64,-115 43.3,-125 43.3,-130 34.64))
POLYGON((-115 25.98,-110 17.32,-100 17.32,-95 25.98,-100 34.64,-110 34.64,-115 25.98))
POLYGON((-115 43.3,-110 34.64,-100 34.64,-95 43.3,-100 51.96,-110 51.96,-115 43.3))
POLYGON((-100 34.64,-95 25.98,-85 25.98,-80 34.64,-85 43.3,-95 43.3,-100 34.64))
As ST_HexagonGrid returns a setof record, you can access the record atributes using a LATERAL as described here, or just call the function in the FROM clause:
SELECT i,j,ST_AsText(geom,2) FROM
ST_HexagonGrid(
10,ST_Buffer('LINESTRING(-105.55 41.11,-115.48 37.16,-109.29 29.38,-98.34 27.13)',1));
i | j | st_astext
----+---+----------------------------------------------------------------------------------------
-8 | 2 | POLYGON((-130 34.64,-125 25.98,-115 25.98,-110 34.64,-115 43.3,-125 43.3,-130 34.64))
-7 | 1 | POLYGON((-115 25.98,-110 17.32,-100 17.32,-95 25.98,-100 34.64,-110 34.64,-115 25.98))
-7 | 2 | POLYGON((-115 43.3,-110 34.64,-100 34.64,-95 43.3,-100 51.96,-110 51.96,-115 43.3))
-6 | 2 | POLYGON((-100 34.64,-95 25.98,-85 25.98,-80 34.64,-85 43.3,-95 43.3,-100 34.64))
Further reading: How to divide world into cells (grid)
I have the following CSV data
"AG","Saint Philip","AG-08"
"AI","Anguilla","-"
"AL","Berat","AL-01"
I want to replace - with NULL
I use the following command
copy subdivision from '/tmp/IP2LOCATION-ISO3166-2.CSV' with delimiter as ',' NULL AS '-' csv;
The copy operation is success. However, - in 3rd column is being copied as well, instead of replaced with NULL.
Do you have idea what mistake in my command? My table is
CREATE TABLE subdivision(
country_code TEXT NOT NULL,
name TEXT NOT NULL,
code TEXT
);
It comes down to the quoting. If you have this:
"AI","Anguilla",-
"AL","Berat","AL-01"
Then the below works(using newer COPY format):
copy
subdivision
from
'/home/postgres/csv_test.csv'
with(format csv, delimiter ',' , NULL '-');
COPY 3
\pset null NULL
select * from subdivision ;
country_code | name | code
--------------+--------------+-------
AG | Saint Philip | AG-08
AI | Anguilla | NULL
AL | Berat | AL-01
If you maintain the original csv:
"AG","Saint Philip","AG-08"
"AI","Anguilla","-"
"AL","Berat","AL-01"
then you have to do this:
copy
subdivision
from
'/home/postgres/csv_test.csv'
with(format csv, delimiter ',' , NULL '-', FORCE_NULL (code) );
select * from subdivision ;
country_code | name | code
--------------+--------------+-------
AG | Saint Philip | AG-08
AI | Anguilla | NULL
AL | Berat | AL-01
where FORCE_NULL is:
https://www.postgresql.org/docs/current/sql-copy.html
FORCE_NULL
Match the specified columns' values against the null string, even if it has been quoted, and if a match is found set the value to NULL. In the default case where the null string is empty, this converts a quoted empty string into NULL. This option is allowed only in COPY FROM, and only when using CSV format.
So to convert quoted values you have to force the conversion by specifying the columns(s)
I have a table in a PostgreSQL database in which I want to store the following columns:
STATION LOCATION SERVICE NORTH EAST
text point text real real
Each tuple(STATION, LOCATION, SERVICE) is unique, so I decided to make it a composite type and make it the primary key.
However, when I try to insert a new entry in the database I get the following error:
psycopg2.ProgrammingError: could not identify a comparison function for type point
I guess it is complaining that you cannot order two points in a 2D plane, but I cannot see how that is relevant. I have managed to use composite types that made use of points as primary keys in a test example, so I cannot see how this is different.
I want to know:
Why this is happening.
How it can be fixed, preferrably without changing the table schema.
Debugging information:
testdb=> \d ERROR_KEY
Composite type "public.error_key"
Column | Type | Modifiers
----------+-------+-----------
station | text |
location | point |
service | text |
testdb=> \d testtable
Table "public.testtable"
Column | Type | Modifiers
--------+-----------+-----------
key | error_key | not null
north | real |
east | real |
Indexes:
"testtable_pkey" PRIMARY KEY, btree (key)
For reference, this is the code I am using for the insertion:
from collections import namedtuple
import psycopg2
DB_NAME = 'testdb'
DB_USER = 'testuser'
DB_HOST = 'localhost'
DB_PASSWORD = '123456'
PVT_TABLE_NAME = 'testtable'
Coordinate = namedtuple('Coordinate', ['lat', 'lon'])
PVT_Error_Key = namedtuple('PVT_Error_Key',
['station', 'location', 'service'])
PVT_Error_Entry = namedtuple(
'PVT_Error_Entry', ['key', 'north', 'east'])
def _adapt_coordinate(coord):
"""
Adapter from Python class to Postgre geometric point
"""
lat = psycopg2.extensions.adapt(coord.lat)
lon = psycopg2.extensions.adapt(coord.lon)
return psycopg2.extensions.AsIs("'(%s, %s)'" % (lat, lon))
def _connect_to_db(db_name, db_user, db_host, db_password):
"""
Connects to a database and returns a cursor object to handle the connection
"""
connection_str = ('dbname=\'%s\' user=\'%s\' host=\'%s\' password=\'%s\''
% (db_name, db_user, db_host, db_password))
return psycopg2.connect(connection_str).cursor()
def main():
# Register the adapter for the location
psycopg2.extensions.register_adapter(Coordinate, _adapt_coordinate)
cursor = _connect_to_db(DB_NAME, DB_USER, DB_HOST, DB_PASSWORD)
# Create a dummy entry
entry = PVT_Error_Entry(
key=PVT_Error_Key(station='GKIR',
location=Coordinate(lat=12, lon=10),
service='E1'),
north=1, east=2)
# Insert the dummy entry in the database
cursor.execute(
'INSERT INTO %s '
'(KEY, NORTH, EAST) '
'VALUES((%%s, %%s, %%s), %%s, %%s)'
% PVT_TABLE_NAME,
(entry.key.station, entry.key.location, entry.key.service,
entry.north, entry.east))
# Retrieve and print all entries of the database
cursor.execute('SELECT * FROM %s', (PVT_TABLE_NAME))
rows = cursor.fetchall()
print(rows)
if __name__ == '__main__':
main()
You cannot use a column of type point in a primary key, e.g.:
create table my_table(location point primary key);
ERROR: data type point has no default operator class for access method "btree"
HINT: You must specify an operator class for the index or define a default operator class for the data type.
The error message is clear enough, you need to create a complete btree operator class for the type.
The full procedure is described in this answer: Creating custom “equality operator” for PostgreSQL type (point) for DISTINCT calls.
Update. With the workaround you mentioned in your comment
create table my_table(
x numeric,
y numeric,
primary key (x, y));
insert into my_table values
(1.1, 1.2);
you can always create a view, which can be queried just like a table:
create view my_view as
select point(x, y) as location
from my_table;
select *
from my_view;
location
-----------
(1.1,1.2)
(1 row)
I have a table EmployeeMoves:
| EmployeeID | CityIDs
+------------------------------
| 24 | 23,21,22
| 25 | 25,12,14
| 29 | 1,2,5
| 31 | 7
| 55 | 11,34
| 60 | 7,9,21,23,30
I'm trying to figure out how to expand the comma-delimited values from the EmployeeMoves.CityIDs column to populate an EmployeeCities table, which should look like this:
| EmployeeID | CityID
+------------------------------
| 24 | 23
| 24 | 21
| 24 | 22
| 25 | 25
| 25 | 12
| 25 | 14
| ... and so on
I already have a function called SplitADelimitedList that splits a comma-delimited list of integers into a rowset. It takes the delimited list as a parameter. The SQL below will give me a table with split values under the column Value:
select value from dbo.SplitADelimitedList ('23,21,1,4');
| Value
+-----------
| 23
| 21
| 1
| 4
The question is: How do I populate EmployeeCities from EmployeeMoves with a single (even if complex) SQL statement using the comma-delimited list of CityIDs from each row in the EmployeeMoves table, but without any cursors or looping in T-SQL? I could have 100 records in the EmployeeMoves table for 100 different employees.
This is how I tried to solve this problem. It seems to work and is very quick in performance.
INSERT INTO EmployeeCities
SELECT
em.EmployeeID,
c.Value
FROM EmployeeMoves em
CROSS APPLY dbo.SplitADelimitedList(em.CityIDs) c;
UPDATE 1:
This update provides the definition of the user-defined function dbo.SplitADelimitedList. This function is used in above query to split a comma-delimited list to table of integer values.
CREATE FUNCTION dbo.fn_SplitADelimitedList1
(
#String NVARCHAR(MAX)
)
RETURNS #SplittedValues TABLE(
Value INT
)
AS
BEGIN
DECLARE #SplitLength INT
DECLARE #Delimiter VARCHAR(10)
SET #Delimiter = ',' --set this to the delimiter you are using
WHILE len(#String) > 0
BEGIN
SELECT #SplitLength = (CASE charindex(#Delimiter, #String)
WHEN 0 THEN
datalength(#String) / 2
ELSE
charindex(#Delimiter, #String) - 1
END)
INSERT INTO #SplittedValues
SELECT cast(substring(#String, 1, #SplitLength) AS INTEGER)
WHERE
ltrim(rtrim(isnull(substring(#String, 1, #SplitLength), ''))) <> '';
SELECT #String = (CASE ((datalength(#String) / 2) - #SplitLength)
WHEN 0 THEN
''
ELSE
right(#String, (datalength(#String) / 2) - #SplitLength - 1)
END)
END
RETURN
END
Preface
This is not the right way to do it. You shouldn't create comma-delimited lists in SQL Server. This violates first normal form, which should sound like an unbelievably vile expletive to you.
It is trivial for a client-side application to select rows of employees and related cities and display this as a comma-separated list. It shouldn't be done in the database. Please do everything you can to avoid this kind of construction in the future. If at all possible, you should refactor your database.
The Right Answer
To get the list of cities, properly expanded, from a table containing lists of cities, you can do this:
INSERT dbo.EmployeeCities
SELECT
M.EmployeeID,
C.CityID
FROM
EmployeeMoves M
CROSS APPLY dbo.SplitADelimitedList(M.CityIDs) C
;
The Wrong Answer
I wrote this answer due to a misunderstanding of what you wanted: I thought you were trying to query against properly-stored data to produce a list of comma-separated CityIDs. But I realize now you wanted the reverse: to query the list of cities using existing comma-separated values already stored in a column.
WITH EmployeeData AS (
SELECT
M.EmployeeID,
M.CityID
FROM
dbo.SplitADelimitedList ('23,21,1,4') C
INNER JOIN dbo.EmployeeMoves M
ON Convert(int, C.Value) = M.CityID
)
SELECT
E.EmployeeID,
CityIDs = Substring((
SELECT ',' + Convert(varchar(max), CityID)
FROM EmployeeData C
WHERE E.EmployeeID = C.EmployeeID
FOR XML PATH (''), TYPE
).value('.[1]', 'varchar(max)'), 2, 2147483647)
FROM
(SELECT DISTINCT EmployeeID FROM EmployeeData) E
;
Part of my difficulty in understanding is that your question is a bit disorganized. Next time, please clearly label your example data and show what you have, and what you're trying to work toward. Since you put the data for EmployeeCities last, it looked like it was what you were trying to achieve. It's not a good use of people's time when questions are not laid out well.