To select from another database I try to use dblink or fdw extension of Postgres, like this:
CREATE EXTENSION dblink;
SELECT * FROM
dblink ('dbname = bd_name port = 5432 host = 10.6.6.6 user = username password = password',
'SELECT id, code FROM sch_schema.table')
AS new_table(id INTEGER, code character varying);
This works fine when I specify which columns I want to select.
My problem is: How can I select all the columns?
I tried this:
SELECT * FROM
dblink ('dbname = bd_name port = 5432 host = 10.6.6.6 user = username password = password',
'SELECT * FROM sch_schema.table');
But this does not work. How can I solve this problem?
You cannot do that, because PostgreSQL must know at query planning time what the columns will be.
But it shouldn't be a problem to specify the columns, and anyway, in most cases it is good practice to avoid the “*” in SQL.
DBLink returns a generic data row type. One of the annoying things about this is that in order to use it, you need to specify the output structure. Perhaps in future versions of PostgreSQL, this limitation of lack of introspection of generic row types will be irradicated. The lack of introspection is an issue not only for DbLink, but for other generic row type returning functions such as TableFunc cross tab functions
Related
I'm trying to run the following PHP script to do a simple database query:
$db_host = "localhost";
$db_name = "showfinder";
$username = "user";
$password = "password";
$dbconn = pg_connect("host=$db_host dbname=$db_name user=$username password=$password")
or die('Could not connect: ' . pg_last_error());
$query = 'SELECT * FROM sf_bands LIMIT 10';
$result = pg_query($query) or die('Query failed: ' . pg_last_error());
This produces the following error:
Query failed: ERROR: relation "sf_bands" does not exist
In all the examples I can find where someone gets an error stating the relation does not exist, it's because they use uppercase letters in their table name. My table name does not have uppercase letters. Is there a way to query my table without including the database name, i.e. showfinder.sf_bands?
From what I've read, this error means that you're not referencing the table name correctly. One common reason is that the table is defined with a mixed-case spelling, and you're trying to query it with all lower-case.
In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to the "search_path" so that when you reference a table name without qualifying its schema, the query will match that table name by checked each schema in order. Just like PATH in the shell or include_path in PHP, etc. You can check your current schema search path:
SHOW search_path
"$user",public
You can change your schema search path:
SET search_path TO showfinder,public;
See also http://www.postgresql.org/docs/8.3/static/ddl-schemas.html
I had problems with this and this is the story (sad but true) :
If your table name is all lower case like : accounts
you can use: select * from AcCounTs and it will work fine
If your table name is all lower case like : accounts
The following will fail:
select * from "AcCounTs"
If your table name is mixed case like : Accounts
The following will fail:
select * from accounts
If your table name is mixed case like : Accounts
The following will work OK:
select * from "Accounts"
I dont like remembering useless stuff like this but you have to ;)
Postgres process query different from other RDMS. Put schema name in double quote before your table name like this, "SCHEMA_NAME"."SF_Bands"
Put the dbname parameter in your connection string. It works for me while everything else failed.
Also when doing the select, specify the your_schema.your_table like this:
select * from my_schema.your_table
If a table name contains underscores or upper case, you need to surround it in double-quotes.
SELECT * from "Table_Name";
I had a similar problem on OSX but tried to play around with double and single quotes. For your case, you could try something like this
$query = 'SELECT * FROM "sf_bands"'; // NOTE: double quotes on "sf_Bands"
This is realy helpfull
SET search_path TO schema,public;
I digged this issues more, and found out about how to set this "search_path" by defoult for a new user in current database.
Open DataBase Properties then open Sheet "Variables"
and simply add this variable for your user with actual value.
So now your user will get this schema_name by defoult and you could use tableName without schemaName.
You must write schema name and table name in qutotation mark. As below:
select * from "schemaName"."tableName";
I had the same issue as above and I am using PostgreSQL 10.5.
I tried everything as above but nothing seems to be working.
Then I closed the pgadmin and opened a session for the PSQL terminal.
Logged into the PSQL and connected to the database and schema respectively :
\c <DATABASE_NAME>;
set search_path to <SCHEMA_NAME>;
Then, restarted the pgadmin console and then I was able to work without issue in the query-tool of the pagadmin.
For me the problem was, that I had used a query to that particular table while Django was initialized. Of course it will then throw an error, because those tables did not exist. In my case, it was a get_or_create method within a admin.py file, that was executed whenever the software ran any kind of operation (in this case the migration). Hope that helps someone.
In addition to Bill Karwin's answer =>
Yes, you should surround the table name with double quotes. However, be aware that most probably php will not allow you to just write simply:
$query = "SELECT * FROM "SF_Bands"";
Instead, you should use single quotes while surrounding the query as sav said.
$query = 'SELECT * FROM "SF_Bands"';
You have to add the schema first e.g.
SELECT * FROM place.user_place;
If you don't want to add that in all queries then try this:
SET search_path TO place;
Now it will works:
SELECT * FROM user_place;
Easiest workaround is Just change the table name and all column names to lowercase and your issue will be resolved.
For example:
Change Table_Name to table_name and
Change ColumnName to columnname
It might be silly for a few, but in my case - once I created the table I could able to query the table on the same session, but if I relogin with new session table does not exits.
Then I used commit just after creating the table and now I could able to find and query the table in the new session as well. Like this:
select * from my_schema.my_tbl;
Hope this would help a few.
Make sure that Table name doesn't contain any trailing whitespaces
Try this: SCHEMA_NAME.TABLE_NAME
I'd suggest checking if you run the migrations or if the table exists in the database.
I tried every good answer ( upvote > 10) but not works.
I met this problem in pgAdmin4.
so my solution is quite simple:
find the target table / scheme.
mouse right click, and click: query-tool
in this new query tool window, you can run your SQL without specifying set search_path to <SCHEMA_NAME>;
you can see the result:
I'm trying to use a query where the schema and table are passed as parameters into a prepared statement using pg_query_params like this:
$searchSchema = 'mySchema';
$searchTable = 'myTable';
$searchColumn = 'searchColumn';
$searchValue = 'some value';
$selQuery = "SELECT *
FROM $1.$2 --fails here
WHERE someColumn like $3;";
$rs = pg_query_params($db, $selQuery , array($searchSchema, $searchTable, $searchColumn, $searchValue));
The issue is with the schema and table which need to be set dynamically - as in the code above.
In a parameterized SQL statement (which is a prepared statement in PostgreSQL), parameters can only stand for constant values, not for table or column names.
This limitation is enforced by PostgreSQL, and there is no way around it, no matter what programming language or driver you use. This is also intentional and not a bug.
You will have to compose a string that contains the complete SQL statement with table and column names substituted and execute that. Beware of SQL injection – use functions like pg_escape_identifier to escape names.
Is there a simple query that will let me distinguish Cloud SQL from stock PostgreSQL? Maybe something like select version() or select current_setting('server_version')?
(I don't have access to a Cloud SQL instance to experiment.)
For the most part, things are the same. You could try looking for the CLOUDSQLSUPERUSER role, which wouldn't existing on regular postgres (unless you or someone else has added it).
EDIT: added #enocom's suggestions for a query to do this:
select * from pg_catalog.pg_user where usename = 'cloudsqlsuperuser';
I'm reviewing log of executed PostgreSQL statements and stumble upon one statement I can't totally understand. Can somebody explain what PostgreSQL actually do when such query is executed? What is siq_query?
select *
from siq_query('', '21:1', '', '("my search string")', False, True, 'http://siqfindex:8080/storediq/findex')
I'm running PostgreSQL 9.2
siq_query(...) is a server-side function taking 7 input parameters (or more). It's not part of any standard Postgres distribution I know (certainly not mainline Postgres 9.2), so it has to be user-defined or part of some extension you installed. It does whatever is defined in the function. This can include basically anything your Postgres user is allowed to do. Unless it's a SECURITY DEFINER function, then it ca do whatever the owner of the function is allowed to do.
The way it is called (SELECT * FROM), only makes sense if it returns multiple rows and/or columns, most likely a set of rows, making it a "set-returning function", which can be used almost like a table in SQL queries.
Since the function name is not schema-qualified, it has to reside in a visible schema. See:
How does the search_path influence identifier resolution and the "current schema"
Long story short, you need to see the function definition to know what it does exactly. You can use psql (\df+ siq_query), pgAdmin (browse and select it to see its definition in the SQL pane) or any other client tool to look it up. Or query the system catalog pg_proc directly:
SELECT * FROM pg_proc WHERE proname = 'siq_query';
Pay special attention to the column prosrc, which holds the function body for some languages like plpgsql.
There might be multiple variants of that name, Postgres allows function overloading.
I'm trying to run the following PHP script to do a simple database query:
$db_host = "localhost";
$db_name = "showfinder";
$username = "user";
$password = "password";
$dbconn = pg_connect("host=$db_host dbname=$db_name user=$username password=$password")
or die('Could not connect: ' . pg_last_error());
$query = 'SELECT * FROM sf_bands LIMIT 10';
$result = pg_query($query) or die('Query failed: ' . pg_last_error());
This produces the following error:
Query failed: ERROR: relation "sf_bands" does not exist
In all the examples I can find where someone gets an error stating the relation does not exist, it's because they use uppercase letters in their table name. My table name does not have uppercase letters. Is there a way to query my table without including the database name, i.e. showfinder.sf_bands?
From what I've read, this error means that you're not referencing the table name correctly. One common reason is that the table is defined with a mixed-case spelling, and you're trying to query it with all lower-case.
In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to the "search_path" so that when you reference a table name without qualifying its schema, the query will match that table name by checked each schema in order. Just like PATH in the shell or include_path in PHP, etc. You can check your current schema search path:
SHOW search_path
"$user",public
You can change your schema search path:
SET search_path TO showfinder,public;
See also http://www.postgresql.org/docs/8.3/static/ddl-schemas.html
I had problems with this and this is the story (sad but true) :
If your table name is all lower case like : accounts
you can use: select * from AcCounTs and it will work fine
If your table name is all lower case like : accounts
The following will fail:
select * from "AcCounTs"
If your table name is mixed case like : Accounts
The following will fail:
select * from accounts
If your table name is mixed case like : Accounts
The following will work OK:
select * from "Accounts"
I dont like remembering useless stuff like this but you have to ;)
Postgres process query different from other RDMS. Put schema name in double quote before your table name like this, "SCHEMA_NAME"."SF_Bands"
Put the dbname parameter in your connection string. It works for me while everything else failed.
Also when doing the select, specify the your_schema.your_table like this:
select * from my_schema.your_table
If a table name contains underscores or upper case, you need to surround it in double-quotes.
SELECT * from "Table_Name";
I had a similar problem on OSX but tried to play around with double and single quotes. For your case, you could try something like this
$query = 'SELECT * FROM "sf_bands"'; // NOTE: double quotes on "sf_Bands"
This is realy helpfull
SET search_path TO schema,public;
I digged this issues more, and found out about how to set this "search_path" by defoult for a new user in current database.
Open DataBase Properties then open Sheet "Variables"
and simply add this variable for your user with actual value.
So now your user will get this schema_name by defoult and you could use tableName without schemaName.
You must write schema name and table name in qutotation mark. As below:
select * from "schemaName"."tableName";
I had the same issue as above and I am using PostgreSQL 10.5.
I tried everything as above but nothing seems to be working.
Then I closed the pgadmin and opened a session for the PSQL terminal.
Logged into the PSQL and connected to the database and schema respectively :
\c <DATABASE_NAME>;
set search_path to <SCHEMA_NAME>;
Then, restarted the pgadmin console and then I was able to work without issue in the query-tool of the pagadmin.
For me the problem was, that I had used a query to that particular table while Django was initialized. Of course it will then throw an error, because those tables did not exist. In my case, it was a get_or_create method within a admin.py file, that was executed whenever the software ran any kind of operation (in this case the migration). Hope that helps someone.
In addition to Bill Karwin's answer =>
Yes, you should surround the table name with double quotes. However, be aware that most probably php will not allow you to just write simply:
$query = "SELECT * FROM "SF_Bands"";
Instead, you should use single quotes while surrounding the query as sav said.
$query = 'SELECT * FROM "SF_Bands"';
You have to add the schema first e.g.
SELECT * FROM place.user_place;
If you don't want to add that in all queries then try this:
SET search_path TO place;
Now it will works:
SELECT * FROM user_place;
Easiest workaround is Just change the table name and all column names to lowercase and your issue will be resolved.
For example:
Change Table_Name to table_name and
Change ColumnName to columnname
It might be silly for a few, but in my case - once I created the table I could able to query the table on the same session, but if I relogin with new session table does not exits.
Then I used commit just after creating the table and now I could able to find and query the table in the new session as well. Like this:
select * from my_schema.my_tbl;
Hope this would help a few.
Make sure that Table name doesn't contain any trailing whitespaces
Try this: SCHEMA_NAME.TABLE_NAME
I'd suggest checking if you run the migrations or if the table exists in the database.
I tried every good answer ( upvote > 10) but not works.
I met this problem in pgAdmin4.
so my solution is quite simple:
find the target table / scheme.
mouse right click, and click: query-tool
in this new query tool window, you can run your SQL without specifying set search_path to <SCHEMA_NAME>;
you can see the result: