Simple question, however google can't help in reasonable time.
Ok, I have user table in my_db database with id column.
I want to run very simple query
SELECT id FROM user;
but it fails.
ERROR: column "id" does not exist LINE 1: SELECT id FROM user;
Can you imagine?
Ok, Running
SELECT * FROM user;
outputs the list of internal postgresql database users, which is nothing to do with my users, it's data from completely another [internal] database.
However, connection with my_db was established.
user is an internal function (and a reserved word) returning the currently logged in user.
To use that as your own identifier, you need to quote it:
select id
from "user"
or
select id
from public."user".
But you should really avoid reserved words as table names (or any name that requires quoting the identifier)
The following query can be rewritten as
SELECT id FROM my_db.public.user;
Where id is column, my_db is database, user is table name, public - is the schema. More about schemas:
http://www.postgresql.org/docs/9.1/static/ddl-schemas.html
So you don't have to rename the table name.
Related
I am not so into PostgreSQL and pgAdmin 4 and I have the following doubt.
Following a screenshot of what I can see in my pgAdmin4:
As you can see it is performing this very simple query:
SELECT * FROM public."Example"
ORDER BY id ASC
The thing that I am not understanding is what is this public name in front of the Example table name. What is it?
I was trying to perform a query in this way but it is not working:
SELECT * FROM Example
ORDER BY id ASC
It give me a syntax error. I often used MySql and in MySql it is working.
I tried to replace the query in this way:
SELECT * FROM "Example"
ORDER BY id ASC
and so it is working. So it means that in PosgreSQL database the "" around the table name are mandatory?
The thing that I am not understanding is what is this public name in front of the Example table name. What is it?
As said in postgres documentation:
"By default tables (and other objects) are automatically put into a schema named "public". Every new database contains such a schema."
So it means that in PosgreSQL database the "" around the table name
are mandatory?
Not really but you need to use it if you are using reserved keywords (such as "user","name"and other)or if your table's name contains uppercase(it's your case) letters. Anyways, in this case if you can it's better change your table's name.
You should change your table name to all alphabet in lowercase then try again with
select * from example
Recently, I want to use psql command line to remove records in user table, but I couldn't get the records inside by using the following command before I delete any of them:
postgres=> select * from user;
But the system returns the DB owner only.
So I am wondering, is the table contents are hidden.
The command used above is checking the database system's internal users. If you want to check client's external users, need to put a double quote on the table name.
postgres=> select * from "user";
Then the table data would be shown .
When collaborating with colleagues I need to change the schema name every time I receive a SQL script (Postgres).
I am only an ordinary user of a corporate database (no permissions to change anything). Also, we are not allowed to create tables in PUBLIC schema. However, we can use (read-only) all the tables from BASE schema.
It is cumbersome for the team of users, where everybody is creating SQL scripts (mostly only for creating tables), which need to be shared amongst others. Every user has its own schema.
Is it possible to change the script below, where I will share the script to another user without the need for the other user to find/replace the schema, in this case, user1?
DROP TABLE IF EXISTS user1.table1;
CREATE TABLE user1.table1 AS
SELECT * FROM base.table1;
You can set the default schema at the start of the script (similar to what pg_dump generates):
set search_path = user1;
DROP TABLE IF EXISTS table1;
CREATE TABLE table1 AS
SELECT * FROM base.table1;
Because the search path was change to contain user1 as the first schema, tables will be searched in that schema when dropping and creating. And because the search path does not include any other schema, no other schema will be consulted.
If you
However the default search_path is "$user", public which means that any unqualified table will be searched or created in a schema with the same name as the current user.
Caution
Note that a DROP TABLE will drop the table in the first schema found in that case. So if table1 doesn't exist in the user's schema, but in the public schema, it would be dropped from the public schema. So for your use-case setting the path to exactly one schema might be more secure.
grails with postgres for User domain.
Message: ERROR: column this_.id does not exist
Got the issue.
For User domain, I've postgres table as "user". So by default when it is trying to query user table, its not querying with "user.id". There is something wrong with postgres for "user" table.
So I updated my "user" table to "myapp_user" table. The problem got solved.
The word 'user' may be reserved by dbms.
static mapping = {
table '`User`'
password column: '`password`'
}
I think it's because table name user already occupied by defalut by Postgres. Try query w/ schema (public by default) like in phpPgAdmin:
SELECT * FROM "public"."user"
All
I am trying to use dblink in PostgreSQL to run query on different databases. The following works if the table "user" is under the public schema:
select * from dblink(
'hostaddr=1.2.3.4 port=5434 dbname=dbname user=username password=password',
'select id from user')
as t1(
id bigint
);
However, I need to run the query on some other defined schemas. Does anyone know how to add the schema information in the above query? I can't figure it out from the PostgreSQL docs.
When you write SQL query like
SELECT id FROM user
PostgreSQL will resolve table name like user into fully qualified name like schema.tablename using schema search path, which by default is set to "$user",public.
In other words, user will resolve into public.user unless you tweaked server configuration.
However, you can specify schema explicitly in your statement, like this:
SELECT id FROM otherschema.user