I have a database in postgreSQL. I want to read some data from there, but I get an error (column anganridref does not exist) when I execute my command.
Here is my NpgsqlCommand:
cmd.CommandText = "select * from angebot,angebotstatus,anrede where anrid=anganridref and anstaid=anganstaidref";
and my 3 tables
the names of my columns are rights. So I don't understand why that error comes. Someone can explain me why it does crash? Its not the problem of large and lowercase.
You are not prefixing your column names in the where clause:
select *
from angebot,
angebotstatus,
anrede
where anrid = anganridref <-- missing tablenames for the columns
and anstaid = anganstaidre
It's also recommended to use an explicit JOIN instead of the old SQL 89 implicit join syntax:
select *
from angebot
join angebotstatus on angebot.aaaa = angebotstatus.bbbb
join anrede on angebot.aaaa = anrede.bbbb
Related
I'm writing a new query postgresql with alias but i still have the same problem of ambiguous column.
select a.id_application
from (SELECT * FROM t_mission as PM
LEFT JOIN t_mission_raf rm on PM.id_mission= rm.id_rm
LEFT JOIN t_mission_roles AS mr ON PM.id_mission = mr.id_mission
LEFT JOIN t_role AS r ON r.id_role = mr.id_role
LEFT JOIN t_appli AS app ON app.id_application = r.id_application
WHERE PM.type_mission = 1 AND PM.id_mission =24730) as a
Result:
Error msg : SQL Error [42702]: ERROR: column reference "id_application" is ambiguous
Position : 8
Don't SELECT * but exlipcitly select the columns you need. Make sure to only select app.id_application or r.id_application. Or use as for one of those.
I don't understand, why the following query produced an error. Whereas in other dbms (eg mysql) this sort of query is absolutely legal.
ERROR: Syntax error at the end of input
LINE 1: SELECT * FROM "addr_country" AS c JOIN "addr_state" AS s
^
SQL state: 42601
Character: 59
Adding an on-clause to the query makes it working:
SELECT * FROM "addr_country" AS c JOIN "addr_state" AS s
ON c."id" = s."country" AND s.id = 10
Due to this answer, MySQL makes a cross join out of a join w/o conditions
I created a temporary table with sqlalchemy (with an underlying postgres database) that is going to be joined with a database table. However, in some cases when a value is empty '' then postgres throws the error:
failed to find conversion function from unknown to text
SqlAlchemy assembles everything to the following context
[SQL: 'WITH temp_table AS \n(SELECT %(param_1)s AS id, %(param_2)s AS email, %(param_3)s AS phone)\n SELECT campaigns_contact.id, campaigns_contact.email, campaigns_contact.phone \nFROM campaigns_contact JOIN temp_table ON temp_table.id = campaigns_contact.id AND temp_table.email = campaigns_contact.email AND temp_table.phone = campaigns_contact.phone'] [parameters: {'param_1': 83, 'param_2': '', 'param_3': '+1234567890'}]
I assemble the temporary table as follows
stmts = []
for row in import_data:
row_values = [literal(row[value]).label(value) for value in values]
stmts.append(select(row_values))
subquery = union_all(*stmts)
subquery = subquery.cte(name="temp_table")
The problem seems to be the part here
...%(param_2)s AS email...
which after replacing the param_2 results in
...'' AS email...
which will cause the error mentioned above.
One way to solve the issue is to perform a cast
...''::text AS email...
However, I don't know how to perform ::text cast with sqlalchemy!?
dont run "select from multiple tables" commands in orientdb 3.0 (centos)
i tested like this following commands
SELECT *
FROM Employee A, City B
WHERE A.city = B.id
Error Codes ; "Error parsing query: ^ Encountered " "SELECT "" at line 1, column 1. Was expecting one of: ... ... ";" ... DB name="
The most important difference between OrientDB and a Relational Database is that relationships are represented by LINKS instead of JOINs.
For this reason, the classic JOIN syntax is not supported. OrientDB uses the "dot (.) notation" to navigate LINKS. Example 1 : In SQL you might create a join such as:
SELECT *
FROM Employee A, City B
WHERE A.city = B.id
AND B.name = 'Rome'
In OrientDB an equivalent operation would be:
SELECT * FROM Employee WHERE city.name = 'Rome'
For more information: https://orientdb.com/docs/2.2.x/SQL.html#joins
Hope it helps
Regards
I have imported one shapefile named tc_bf25 using qgis, and the following is my python script typed in pyscripter,
import sys
import psycopg2
conn = psycopg2.connect("dbname = 'routing_template' user = 'postgres' host = 'localhost' password = '****'")
cur = conn.cursor()
query = """
ALTER TABLE tc_bf25 ADD COLUMN source integer;
ALTER TABLE tc_bf25 ADD COLUMN target integer;
SELECT assign_vertex_id('tc_bf25', 0.0001, 'the_geom', 'gid')
;"""
cur.execute(query)
query = """
CREATE OR REPLACE VIEW tc_bf25_ext AS
SELECT *, startpoint(the_geom), endpoint(the_geom)
FROM tc_bf25
;"""
cur.execute(query)
query = """
CREATE TABLE node1 AS
SELECT row_number() OVER (ORDER BY foo.p)::integer AS id,
foo.p AS the_geom
FROM (
SELECT DISTINCT tc_bf25_ext.startpoint AS p FROM tc_bf25_ext
UNION
SELECT DISTINCT tc_bf25_ext.endpoint AS p FROM tc_bf25_ext
) foo
GROUP BY foo.p
;"""
cur.execute(query)
query = """
CREATE TABLE network1 AS
SELECT a.*, b.id as start_id, c.id as end_id
FROM tc_bf25_ext AS a
JOIN node AS b ON a.startpoint = b.the_geom
JOIN node AS c ON a.endpoint = c.the_geom
;"""
cur.execute(query)
query = """
ALTER TABLE network1 ADD COLUMN shape_leng double precision;
UPDATE network1 SET shape_leng = length(the_geom)
;"""
cur.execute(query)
I got the error at the second cur.execute(query),
But I go to pgAdmin to check result, even though no error occurs, the first cur.execute(query) didn't add new columns in my table.
What mistake did I make？ And how to fix it？
I am working with postgresql 8.4, python 2.7.6 under Windows 8.1 x64.
When using psycopg2, autocommit is set to False by default. The first two statements both refer to table tc_bf25, but the first statement makes an uncommitted change to the table. So try running conn.commit() between statements to see if this resolves the issue
You should run each statement individually. Do not combine multiple statements into a semicolon separated series and run them all at one. It makes error handling and fetching of results much harder.
If you still have the problem once you've made that change, show the exact statement you're having the problem with.
Just to add to #Talvalin you can enable auto-commit by adding
psycopg2.connect("dbname='mydb',user='postgres',host ='localhost',password = '****'")
conn.autocommit = True
after you connect to your database using psycopg2