Variable declaration in postgres - postgresql

How to create variable with two word separated by space in Postgresql.
CREATE TABLE Test(
Partner varchar(10) NULL,
"[Partner Name]" varchar (200) NULL,
"[Contract Number]" varchar(15) NULL,
"[Customer Name]" varchar(150) NULL,
"[Lease Start]" Date date NULL
From maintable
This is not working. How to give variables with 2 words separated by space. Please help

Seems you want to populate the data in new table named test from other table named maintable with column names having spaces.
below is the syntax
CREATE TABLE Test
as select col1 as Partner ,
col2 as "Partner Name",
col3 as "Contract Number",
col4 as "Customer Name",
col5 as "Lease Start Date" from maintable;

Related

can't import files csv in pgAdmin 4

i will import data csv to postgresql via pgAdmin 4. But, there are problem
ERROR: invalid input syntax for type integer: ""
CONTEXT: COPY films, line 1, column gross: ""
i understand about the error that is line 1 column gross there is null value and in some other columns there are also null values. My questions, how to import file csv but in the that file there is null value. I've been search in google but not found similar my case.
CREATE TABLE public.films
(
id int,
title varchar,
release_year float4,
country varchar,
duration float4,
language varchar,
certification varchar,
gross int,
budget int
);
And i try in this code below, but failed
CREATE TABLE public.films
(
id int,
title varchar,
release_year float4 null,
country varchar null,
duration float4 null,
language varchar null,
certification varchar null,
gross float4 null,
budget float4 null
);
error message in image
I've searched on google and on the stackoverflow forums. I hope that someone will help solve my problem
There is no difference between the two table definitions. A column accepts NULL by default.
The issue is not a NULL value but an empty string:
select ''::integer;
ERROR: invalid input syntax for type integer: ""
LINE 1: select ''::integer;
select null::integer;
int4
------
NULL
Create a staging table that has data type of varchar for the fields that are now integer. Load the data into that table. Then modify the empty string data that will be integer using something like:
update table set gross = nullif(trim(gross), '');
Then move the data to the production table.
This is not a pgAdmin4 issue it is a data issue. Working in psql because it is easier to follow:
CREATE TABLE public.films_text
(
id varchar,
title varchar,
release_year varchar,
country varchar,
duration varchar,
language varchar,
certification varchar,
gross varchar,
budget varchar
);
\copy films_text from '~/Downloads/films.csv' with csv
COPY 4968
CREATE TABLE public.films
(
id int,
title varchar,
release_year float4,
country varchar,
duration float4,
language varchar,
certification varchar,
gross int,
budget int
);
-- Below done because of this value 12215500000 in budget column
alter table films alter COLUMN budget type int8;
INSERT INTO films
SELECT
id::int,
title,
nullif (trim(release_year), '')::real, country, nullif(trim(duration), '')::real,
LANGUAGE,
certification,
nullif (trim(gross), '')::float, nullif(trim(budget), '')::float
FROM
films_text;
INSERT 0 4968
It worked for me:
https://learnsql.com/blog/how-to-import-csv-to-postgresql/
a small workaround but it works
I created a table
I added headers to csv file
Right click on the newly created table-> Import/export data, select csv file to upload, go to tab2 - select Header and it should work

A view that shows the name of the server, the id of the instance and the number of active sessions (a session is active if the end timestamp is null)

CREATE TABLE instances(
ser_name VARCHAR(20) NOT NULL,
id INTEGER NOT NULL ,
ser_ip VARCHAR(16) NOT NULL,
status VARCHAR(10) NOT NULL,
creation_ts TIMESTAMP,
CONSTRAINT instance_id PRIMARY KEY(id)
);
CREATE TABLE characters(
nickname VARCHAR(15) NOT NULL,
type VARCHAR(10) NOT NULL,
c_level INTEGER NOT NULL,
game_data VARCHAR(40) NOT NULL,
start_ts TIMESTAMP ,
end_ts TIMESTAMP NULL ,
player_ip VARCHAR(16) NOT NULL,
instance_id INTEGER NOT NULL,
player_username VARCHAR(15),
CONSTRAINT chara_nick PRIMARY KEY(nickname)
);
ALTER TABLE
instances ADD CONSTRAINT ins_ser_name FOREIGN KEY(ser_name) REFERENCES servers(name);
ALTER TABLE
instances ADD CONSTRAINT ins_ser_ip FOREIGN KEY(ser_ip) REFERENCES servers(ip);
ALTER TABLE
characters ADD CONSTRAINT chara_inst_id FOREIGN KEY(instance_id) REFERENCES instances(id);
ALTER TABLE
characters ADD CONSTRAINT chara_player_username FOREIGN KEY(player_username) REFERENCES players(username);
insert into instances values
('serverA','1','138.201.233.18','active','2020-10-20'),
('serverB','2','138.201.233.19','active','2020-10-20'),
('serverE','3','138.201.233.14','active','2020-10-20');
insert into characters values
('characterA','typeA','1','Game data of characterA','2020-07-18 02:12:12','2020-07-18 02:32:30','192.188.11.1','1','nabin123'),
('characterB','typeB','3','Game data of characterB','2020-07-19 02:10:12',null,'192.180.12.1','2','rabin123'),
('characterC','typeC','1','Game data of characterC','2020-07-18 02:12:12',null,'192.189.10.1','3','sabin123'),
('characterD','typeA','1','Game data of characterD','2020-07-18 02:12:12','2020-07-18 02:32:30','192.178.11.1','2','nabin123'),
('characterE','typeB','3','Game data of characterE','2020-07-19 02:10:12',null,'192.190.12.1','1','rabin123'),
('characterF','typeC','1','Game data of characterF','2020-07-18 02:12:12',null,'192.188.10.1','3','sabin123'),
('characterG','typeD','1','Game data of characterG','2020-07-18 02:12:12',null,'192.188.13.1','1','nabin123'),
('characterH','typeD','3','Game data of characterH','2020-07-19 02:10:12',null,'192.180.17.1','2','bipin123'),
('characterI','typeD','1','Game data of characterI','2020-07-18 02:12:12','2020-07-18 02:32:30','192.189.18.1','3','dhiraj123'),
('characterJ','typeD','3','Game data of characterJ','2020-07-18 02:12:12',null,'192.178.19.1','2','prabin123'),
('characterK','typeB','4','Game data of characterK','2020-07-19 02:10:12','2020-07-19 02:11:30','192.190.20.1','1','rabin123'),
('characterL','typeC','2','Game data of characterL','2020-07-18 02:12:12',null,'192.192.11.1','3','sabin123'),
('characterM','typeC','3','Game data of characterM','2020-07-18 02:12:12',null,'192.192.11.1','2','sabin123');
here I need a view that shows the name of the server, the id of the instance and the number of active sessions (a session is active if the end timestamp is null). do my code wrong or something else? i am starting to learn so hoping for positive best answers.
my view
create view active_sessions as
select i.ser_name, i.id, count(end_ts) as active
from instances i, characters c
where i.id=c.instance_id and c.end_ts = null
group by i.ser_name, i.id;
This does not do what you want:
where i.id = c.instance_id and c.end_ts = null
Nothing is equal to null. You need is null to check a value against null.
Also, count(end_ts) will always produce 0, as we know already that end_ts is null, which count() does not consider.
Finally, I would highly recommend using a standard join (with the on keyword), rather than an implicit join (with a comma in the from clause): this old syntax from decades ago should not be used in new code. I think that a left join is closer to what you want (it would also take in account instances that have no character at all).
So:
create view active_sessions as
select i.ser_name, i.id, count(c.nickname) as active
from instances i
left join characters c on i.id = c.instance_id and c.end_ts is null
group by i.ser_name, i.id;

design of table with checked column or column with reference to primary key which is updatable

I faced a problem when creating/designing tables in DB2.
I have two tables, table users and table countries created as shown bellow
create table users
(
firstname varchar(20) not null,
lastname varchar(20) not null,
gender char(1) not null check (gender in ('M','F')),
birthdate date not null,
country char(3) not null,
)
create table testing.countries
(
name varchar(60) not null,
code2 char(2) not null,
code3 char(3) not null
)
I want to have in a column country in table users a 3-char code of a country of origin and during insertion of data to be checked if it is valid (or better to say if it exists) from the list of countries which are stored in table countries.
Because DB2 doesn't support a subquery/subselect in a check option (which would be the best for me) then it looks like a candidate for a foreign key on column country in users referencing to a primary key on column code3 in countries. But in case there will be update of 3-char code of any country, it will be impossible to update it in simple way.
I know that the update of this will not be so often and can be done manually by first inserting new data to countries, then updating values in users and then deleting the old values in countries but unfortunately there will be more similar tables where data will have to be checked during insertion against another table and data in referenced table will be updated quite often and then the manual update is uncomfortable. And of course I want the data in users to be updated in case the update in countries will be done.
What I want to ask is how to solve this. I thought about some before or instead of trigger but BEFORE cannot be used to change data in other tables and INSTEAD OF is expecting UNTYPED VIEW not the TABLE
SQL0159N The statement references an object that identifies an unexpected
object type. Object: "COUNTRIES". Object type: "TABLE". Expected object type:
"UNTYPED VIEW". LINE NUMBER=2. SQLSTATE=42809`
Can you please advise me?
Thanks in advance
try Something like this:
create table testing.users
(
firstname varchar(20) not null,
lastname varchar(20) not null,
gender char(1) not null check (gender in ('M','F')),
birthdate date not null,
country char(3) not null
)
create table testing.countries
(
name varchar(60) not null,
code2 char(2) not null,
code3 char(3) not null
)
ALTER TABLE testing.users ADD CONSTRAINT testing.PK_Users PRIMARY KEY
(firstname, lastname);
ALTER TABLE testing.countries ADD CONSTRAINT testing.PK_Countries PRIMARY KEY
(code3);
ALTER TABLE testing.users ADD CONSTRAINT testing.FK_Users_Countries FOREIGN KEY
(country)
REFERENCES testing.users
(code3)
ON DELETE CASCADE;

T-SQL 'Cannot insert the value NULL' error with non-NULL values

I'm migrating a Simple Membership database to Identity 2.0. I'm copying a CreateDate datetime NULL column to a CreateDate datetime NOT NULL column. I've examined all the records in the Membership.CreateDate column in the data source table to verify that they contain valid DateTimes. This error is returned:
Cannot insert the value NULL into column 'CreateDate', table 'Settlement.dbo.AspNetUsers'; column does not allow nulls. INSERT fails.
The statement has been terminated.
I've also tried deleting all the records in Membership but one (its CreateDate column contains 2012-12-27 01:35:03.610). I get the same error.
I'm running the script in SSMS.
Migration script excerpts:
CREATE TABLE [dbo].[AspNetUsers] (
[Id] [nvarchar](60) NOT NULL,
[UserName] [nvarchar](15) NOT NULL,
[AcId] INT NOT NULL,
[LocId] INT NOT NULL,
[CreateDate] [datetime] NOT NULL,
[Email] [nvarchar](60),
[EmailConfirmed] [bit] Default ((0)) NOT NULL,
[PasswordHash] [nvarchar] (100),
[SecurityStamp] [nvarchar] (60),
[PhoneNumber] [nvarchar] (15),
[PhoneNumberConfirmed] [bit] Default ((0)) NOT NULL,
[TwoFactorEnabled] [bit] Default ((0)) NOT NULL,
[LockoutEndDateUtc] [datetime],
[LockoutEnabled] [bit] Default ((0)) NOT NULL,
[AccessFailedCount] [int] Default ((0)) NOT NULL,
CONSTRAINT [PK_dbo.AspNetUsers] PRIMARY KEY ([Id])
);
GO
INSERT INTO AspNetUsers(Id, UserName, AcId, LocId, PasswordHash, SecurityStamp, CreateDate )
SELECT UserProfile.UserId, UserProfile.UserName, UserProfile.BaId, UserProfile.OfcId,
webpages_Membership.Password, webpages_Membership.PasswordSalt, webpages_Membership.CreateDate
FROM UserProfile
LEFT OUTER JOIN webpages_Membership ON UserProfile.UserId = webpages_Membership.UserId
GO
If I change the AspNetUsers CreateDate column to NULL it successfully copies the datetimes from table to table so I know all the column names and types are correct.
(After doing this I ran
ALTER TABLE [dbo].[AspNetUsers] ALTER COLUMN [CreateDate] datetime NOT NULL
and got the same error)
This is happening with the Production copy of the database. I have a development copy of the database generated through the same EF code first code and it successfully copies the data into the CreateDate NOT NULL field.
I'm at wits end at this point. Why am I getting a Cannot insert the value NULL into column error when the source data is valid datetimes? Or why doesn't it recognize the CreateDate columns data as valid datetimes?
You have some users in the UserProfile that haven't corresponding users in the webpages_Membership, so you try to insert users without any information. You must use INNER JOIN instead of LEFT OUTER JOIN or provide the default values for users which haven't corresponding information.

How to change the table name during the runtime

I have the following,
create table ssrr_emp(
Emp_name varchar2(25),
Emp_city varchar2(10),
Emp_id number(2)
);
/
create table ssrr_empsal(
sal_grade char(1),
salary number(7,2),
Commission number(5)
);
/
In the above code,the table names are prefixed with ssrr i.e ssrr_emp and ssrr_empsal,
Here my question is when I am executing the above code
I need to prefix the table name with er i.e er_emp and er_empsal.
I mean during the runtime it should ask the name to enter only for ssrr,
and
if i enter er then the tables should be created in the name er_emp and er_empsal.
If you're using SQL*Plus, you can use substitution variables with &, e.g.:
create table &&PREFIX._emp(
Emp_name varchar2(25),
Emp_city varchar2(10),
Emp_id number(2)
);
/
create table &&PREFIX._empsal(
sal_grade char(1),
salary number(7,2),
Commission number(5)
);
/
When you run the script, it will prompt you for the value:
Enter value for prefix: