I have these three tables for services, executed_services and a rating table, which rates the service. My rating table has a foreign key to executed_services, and so, I wanted to "copy" the service to be rated to the executed_services relation. I tried using the following procedure, but this select won't work, as it has to return only one result.
BEGIN
INSERT INTO servico_executado (id, data_abertura, id_solicitacao, id_profissional)
VALUES (SELECT id, data_abertura, id_solicitacao, id_profissional FROM servico WHERE id = NEW.id_servico);
DELETE FROM servico WHERE id = NEW.id_servico;
RETURN NEW;
END;
So, what should I do to get all the values from one table and insert on another? Or is there other way to do that?
You can do it very easily in one step with a CTE with the following simple query:
WITH deleted AS (DELETE FROM servico WHERE id = $1 RETURNING *)
INSERT INTO servico_executado (id, data_abertura, id_solicitacao, id_profissional)
SELECT id, data_abertura, id_solicitacao, id_profissional FROM deleted
RETURNING *;
There is no need to use PL/pgSQL. The id of the service moved is denoted by the placeholder $1 in the above query.
INSERT INTO servico_executado
SELECT id, data_abertura, id_solicitacao, id_profissional
FROM servico WHERE id = NEW.id_servico;
Do not use 'VALUES'. If you have more columns in the table, you can use null in the select statement for those missing columns.
Related
I have a demo table
CREATE TABLE items (
id SERIAL primary key,
user_id integer,
name character varying,
created timestamp with time zone default now()
);
And I want a single query to run and first insert data, then return primary key using returning id and then update the same table with the returned id.
INSERT INTO items (name) values ('pen') RETURNING id as idd
update items set user_id=(select idd) where id=(select idd)
but the above command doesn't work and throws syntax error.
Any help will be appriciated.
You can do that right within the INSERT statement:
INSERT INTO items
(name, user_id)
values
('pen', currval(pg_get_serial_sequence('items','id')));
Online example
You can try this way also :
create temp table insert_item as
with insert_item_cte as (
INSERT INTO items (name)
values ('pen') returning id
)
select id from insert_item_cte;
update items set user_id = items.id
from insert_item ii
where ii.id = items.id;
Online Demo
I have a table with records which can reference another row in the same table so there is a parent-child relationship between rows in the same table.
What I am trying to achieve is to create the same data for another user so that they can see and manage their own version of this structure through the web ui where these rows are displayed as a tree.
Problem is when I bulk insert this data by only changing user_id, I lose the relation between rows because the parent_id values will be invalid for these new records and they should be updated as well with the newly generated ids.
Here is what I tried: (did not work)
Iterate over main_table
copy-paste the static values after each
do another insert on a temp table for holding old and new ids
update old parent_ids with new ids after loop ends
My attempt at doing such thing(last step is not included here)
create or replace function test_x()
returns void as
$BODY$
declare
r RECORD;
userId int8;
rowPK int8;
begin
userId := (select 1)
create table if not exists id_map (old_id int8, new_id int8);
create table if not exists temp_table as select * from main_table;
for r in select * from temp_table
loop
rowPK := insert into main_table(id, user_id, code, description, parent_id)
values(nextval('hibernate_sequence'), userId, r.code, r.description, r.parent_id) returning id;
insert into id_map (old_id, new_id) values (r.id, rowPK);
end loop;
end
$BODY$
language plpgsql;
My PostgreSQL version is 9.6.14.
DDL below for testing.
create table main_table(
id bigserial not null,
user_id int8 not null,
code varchar(3) not null,
description varchar(100) not null,
parent_id int8 null,
constraint mycompkey unique (user_id, code, parent_id),
constraint mypk primary key (id),
constraint myfk foreign key (parent_id) references main_table(id)
);
insert into main_table (id, user_id, code, description, parent_id)
values(0, 0, '01', 'Root row', null);
insert into main_table (id, user_id, code, description, parent_id)
values(1, 0, '001', 'Child row 1', 0);
insert into main_table (id, user_id, code, description, parent_id)
values(2, 0, '002', 'Child row 2', 0);
insert into main_table (id, user_id, code, description, parent_id)
values(3, 0, '002', 'Grand child row 1', 2);
How to write a procedure to accomplish this?
Thanks in advance.
It appears your task is coping all data for a given user to another while maintaining the hierarchical relationship within the new rows. The following accomplishes that.
It begins creating a new copy of the existing rows with the new user_id, including the old row parent_id. That will be user in the next (update) step.
The CTE logically begins with the new rows which have parent_id and joins to the old parent row. From here it joins to the old parent row to the new parent row using the code and description. At that point we have the new id along with the new parent is. At that point just update with those values. Actually for the update the CTE need only select those two columns, but I've left the intermediate columns so you trace through if you wish.
create or replace function copy_user_data_to_user(
source_user_id bigint
, target_user_id bigint
)
returns void
language plpgsql
as $$
begin
insert into main_table ( user_id,code, description, parent_id )
select target_user_id, code, description, parent_id
from main_table
where user_id = source_user_id ;
with n_list as
(select mt.id, mt.code, mt.description, mt.parent_id
, mtp.id p_id,mtp.code p_code,mtp.description p_des
, mtc.id c_id, mtc.code c_code, mtc.description c_description
from main_table mt
join main_table mtp on mtp.id = mt.parent_id
join main_table mtc on ( mtc.user_id = target_user_id
and mtc.code = mtp.code
and mtc.description = mtp.description
)
where mt.parent_id is not null
and mt.user_id = target_user_id
)
update main_table mt
set parent_id = n_list.c_id
from n_list
where mt.id = n_list.id;
return;
end ;
$$;
-- test
select * from copy_user_data_to_user(0,1);
select * from main_table;
CREATE TABLE 'table name you want to create' SELECT * FROM myset
but new table and myset column name should be equal and you can also
use inplace of * to column name but column name exist in new table
othwerwise getting errors
I have two tables, cinema and theater.
Table Cinema
Columns:
id, name, is_active
Table Theater
Columns:
id, cinema_id
I'm doing insertion into the DB, in sequence. First, I'll insert into cinema and then into theater. The cinema_id.theater is a foreign key that reference cinema.id. After the insertion into cinema, I'll insert data into the theater, but I need the value from cinema's id before insert the data in cinema_id.
I was thinking about RETURNING id INTO cinema_id and, then, save into theater. But I really don't know how I can possibly do something like this.
Any thoughts? Is there any better way to do something like this?
You have two options.
The first one is using the lastval() function which returns the value of the last generated sequence value:
insert into cinema(name, is_active) values ('Cinema One', true);
insert into theater(cinema_id) values (lastval());
Alternatively you can pass the sequence name to the currval() function:
insert into theater(cinema_id)
values (currval(pg_get_serial_sequence('cinema', 'id')));
Alternatively you can chain the two statements using a CTE and the returning clause:
with new_cinema as (
insert into cinema (name, is_active)
values ('Cinema One', true)
returning id
)
insert into theater (cinema_id)
select id
from new_cinema;
In both statements I assume theater.id is also a generated value.
this way works.
with new_cinema as (
insert into cinema (name, is_active)
values ('Cinema One', true)
returning id
)
insert into theater (cinema_id)
select id
from new_cinema;
INSERT INTO tableB
(
columnA
)
SELECT
columnA
FROM
tableA
ORDER BY columnA desc
LIMIT 1
I know the title may seem strange but this is what I want to do:
I have table with many records.
I want to get some of this records and insert them in other table. Something like this:
INSERT INTO TableNew SELECT * FROM TableOld WHERE ...
The tricky part is that I want this rows that I have inserted to be deleted form the origin table as well.
Is there a easy way to do this, because the only think that I have managed to do is to use a temporary table for saving the selected records and then to put them in the second table and delete rows that match with them from the first table. It is a solution, but with so many records (over 3 millions and half) I am looking for some other idea...
In 2005+ use OUTPUT clause like this:
DELETE FROM TableOld
OUTPUT DELETED.* INTO TableNew
WHERE YourCondition
It will be performed in single transaction and either completed or roll back simultaneously
You can use the insert ... output clause to store the ID's of the copied rows in a temporary table. Then you can delete the rows from the original table based on the temporary table.
declare #Table1 table (id int, name varchar(50))
declare #Table2 table (id int, name varchar(50))
insert #Table1 (id,name)
select 1, 'Mitt'
union all select 2, 'Newt'
union all select 3, 'Rick'
union all select 4, 'Ron'
declare #copied table (id int)
insert #Table2
(id, name)
output inserted.id
into #copied
select id
, name
from #Table1
where name <> 'Mitt'
delete #Table1
where id in
(
select id
from #copied
)
select *
from #Table1
Working example at Data Explorer.
You should do some thing like this:
INSERT INTO "table1" ("column1", "column2", ...)
SELECT "column3", "column4", ...
FROM "table2"
WHERE ...
DELETE FROM "table1"
WHERE ...
I'm using PostgreSQL 9.0 and I have a table with just an artificial key (auto-incrementing sequence) and another unique key. (Yes, there is a reason for this table. :)) I want to look up an ID by the other key or, if it doesn't exist, insert it:
SELECT id
FROM mytable
WHERE other_key = 'SOMETHING'
Then, if no match:
INSERT INTO mytable (other_key)
VALUES ('SOMETHING')
RETURNING id
The question: is it possible to save a round-trip to the DB by doing both of these in one statement? I can insert the row if it doesn't exist like this:
INSERT INTO mytable (other_key)
SELECT 'SOMETHING'
WHERE NOT EXISTS (SELECT * FROM mytable WHERE other_key = 'SOMETHING')
RETURNING id
... but that doesn't give the ID of an existing row. Any ideas? There is a unique constraint on other_key, if that helps.
Have you tried to union it?
Edit - this requires Postgres 9.1:
create table mytable (id serial primary key, other_key varchar not null unique);
WITH new_row AS (
INSERT INTO mytable (other_key)
SELECT 'SOMETHING'
WHERE NOT EXISTS (SELECT * FROM mytable WHERE other_key = 'SOMETHING')
RETURNING *
)
SELECT * FROM new_row
UNION
SELECT * FROM mytable WHERE other_key = 'SOMETHING';
results in:
id | other_key
----+-----------
1 | SOMETHING
(1 row)
No, there is no special SQL syntax that allows you to do select or insert. You can do what Ilia mentions and create a sproc, which means it will not do a round trip fromt he client to server, but it will still result in two queries (three actually, if you count the sproc itself).
using 9.5 i successfully tried this
based on Denis de Bernardy's answer
only 1 parameter
no union
no stored procedure
atomic, thus no concurrency problems (i think...)
The Query:
WITH neworexisting AS (
INSERT INTO mytable(other_key) VALUES('hello 2')
ON CONFLICT(other_key) DO UPDATE SET existed=true -- need some update to return sth
RETURNING *
)
SELECT * FROM neworexisting
first call:
id|other_key|created |existed|
--|---------|-------------------|-------|
6|hello 1 |2019-09-11 11:39:29|false |
second call:
id|other_key|created |existed|
--|---------|-------------------|-------|
6|hello 1 |2019-09-11 11:39:29|true |
First create your table ;-)
CREATE TABLE mytable (
id serial NOT NULL,
other_key text NOT NULL,
created timestamptz NOT NULL DEFAULT now(),
existed bool NOT NULL DEFAULT false,
CONSTRAINT mytable_pk PRIMARY KEY (id),
CONSTRAINT mytable_uniq UNIQUE (other_key) --needed for on conflict
);
you can use a stored procedure
IF (SELECT id FROM mytable WHERE other_key = 'SOMETHING' LIMIT 1) < 0 THEN
INSERT INTO mytable (other_key) VALUES ('SOMETHING')
END IF
I have an alternative to Denis answer, that I think is less database-intensive, although a bit more complex:
create table mytable (id serial primary key, other_key varchar not null unique);
WITH table_sel AS (
SELECT id
FROM mytable
WHERE other_key = 'test'
UNION
SELECT NULL AS id
ORDER BY id NULLS LAST
LIMIT 1
), table_ins AS (
INSERT INTO mytable (id, other_key)
SELECT
COALESCE(id, NEXTVAL('mytable_id_seq'::REGCLASS)),
'test'
FROM table_sel
ON CONFLICT (id) DO NOTHING
RETURNING id
)
SELECT * FROM table_ins
UNION ALL
SELECT * FROM table_sel
WHERE id IS NOT NULL;
In table_sel CTE I'm looking for the right row. If I don't find it, I assure that table_sel returns at least one row, with a union with a SELECT NULL.
In table_ins CTE I try to insert the same row I was looking for earlier. COALESCE(id, NEXTVAL('mytable_id_seq'::REGCLASS)) is saying: id could be defined, if so, use it; whereas if id is null, increment the sequence on id and use this new value to insert a row. The ON CONFLICT clause assure
that if id is already in mytable I don't insert anything.
At the end I put everything together with a UNION between table_ins and table_sel, so that I'm sure to take my sweet id value and execute both CTE.
This query needs to search for the value other_key only once, and is a "search this value" not a "check if this value not exists in the table", that is very heavy; in Denis alternative you use other_key in both types of searches. In my query you "check if a value not exists" only on id that is a integer primary key, that, for construction, is fast.
Minor tweak a decade late to Denis's excellent answer:
-- Create the table with a unique constraint
CREATE TABLE mytable (
id serial PRIMARY KEY
, other_key varchar NOT NULL UNIQUE
);
WITH new_row AS (
-- Only insert when we don't find anything, avoiding a table lock if
-- possible.
INSERT INTO mytable ( other_key )
SELECT 'SOMETHING'
WHERE NOT EXISTS (
SELECT *
FROM mytable
WHERE other_key = 'SOMETHING'
)
RETURNING *
)
(
-- This comes first in the UNION ALL since it'll almost certainly be
-- in the query cache. Marginally slower for the insert case, but also
-- marginally faster for the much more common read-only case.
SELECT *
FROM mytable
WHERE other_key = 'SOMETHING'
-- Don't check for duplicates to be removed
UNION ALL
-- If we reach this point in iteration, we needed to do the INSERT and
-- lock after all.
SELECT *
FROM new_row
) LIMIT 1 -- Just return whatever comes first in the results and allow
-- the query engine to cut processing short for the INSERT
-- calculation.
;
The UNION ALL tells the planner it doesn't have to collect results for de-duplication. The LIMIT 1 at the end allows the planner to short-circuit further processing/iteration once it knows there's an answer available.
NOTE: There is a race condition present here and in the original answer. If the entry does not already exist, the INSERT will fail with a unique constraint violation. The error can be suppressed with ON CONFLICT DO NOTHING, but the query will return an empty set instead of the new row. This is a difficult problem because getting that info from another transaction would violate the I in ACID.