How to use WHILE EXISTS in a loop - tsql

CREATE TABLE [CandidateDocsAssociation](
[Row_ID] [bigint] IDENTITY(1,1) NOT NULL,
[Doc_ID] [bigint] NOT NULL,
[Candidate_ID] [bigint] NOT NULL,
) ON [PRIMARY]
GO
I have the above table structure to store the association between documents and candidates. Row_ID is an auto generated primary key. Doc_ID is a foreign key referencing the documents table. Candidate_ID is also a foreign key referencing the Candidates table.
A candidate can be associated with more than one document and one document can be associated with multiple candidates.
What i want to achieve is insert a default common document (Doc_ID) for all candidates(DISTINCT) if a Candidate_ID row with a DOC_ID of 2 does not already exist.
Below is what i'm trying but it ain't working
WHILE EXISTS (SELECT DISTINCT Candidate_ID from CandidateDocsAssociation
WHERE Doc_ID <> (SELECT Doc_ID FROM Doc_Table WHERE Doc_Name = N'Default'))
BEGIN
INSERT CandidateDocsAssociation (Doc_ID, Candidate_ID) VALUES ((SELECT Doc_ID FROM Doc_Table WHERE Doc_Name = N'Default'),Candidate_ID)
END
GO

Forget the loop and do a set-based operation. Assuming you have a Candidates table:
INSERT INTO CandidateDocsAssociation (Doc_ID, Candidate_ID)
SELECT dt.Doc_ID, c.Candidate_ID
FROM Doc_Table dt
CROSS JOIN Candidates c
WHERE dt.Doc_Name = N'Default'
AND NOT EXISTS(SELECT * FROM CandidateDocsAssociation cda
WHERE cda.Candidate_ID=c.Candidate_ID
AND cda.Doc_ID=dt.Doc_ID)

try with this (use NOT IN Clause)
WHILE EXISTS (SELECT DISTINCT Candidate_ID from CandidateDocsAssociation
WHERE Doc_ID NOT IN (SELECT Doc_ID FROM Doc_Table WHERE Doc_Name = N'Default'))
BEGIN
INSERT CandidateDocsAssociation (Doc_ID, Candidate_ID) VALUES ((SELECT Doc_ID FROM Doc_Table WHERE Doc_Name = N'Default'),Candidate_ID)
END
GO

Related

How to pull out records based on array of values

Suppose the following structure:
CREATE SCHEMA IF NOT EXISTS my_schema;
CREATE TABLE IF NOT EXISTS my_schema.user (
id SERIAL PRIMARY KEY,
tag_id BIGINT NOT NULL
);
CREATE TABLE IF NOT EXISTS my_schema.conversation (
id SERIAL PRIMARY KEY,
user_ids BIGINT[] NOT NULL
);
INSERT INTO my_schema.user VALUES
(1, 55555),
(2, 77777);
INSERT INTO my_schema.conversation VALUES
(1, '{1,2}');
I can pull out the my_schema.conversation records if I know the my_schema.user.id values:
SELECT *
FROM my_schema.conversation
WHERE user_ids #> '{1}'
The above works, but I need to use my_schema.user.tag_id instead of my_schema.user.id:
How can I do this?
Fiddle
You would have to join the two tables on the array values
SELECT *
FROM my_schema.user u
JOIN my_schema.conversation c
ON u.id = any(c.chat_ids)
WHERE u.tag_id=55555;

Copying records in a table with self referencing ids

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

PostgreSQL count other values of ID that have the same value of other column

Let's say we have the following table that stores id of an observation and its address_id. You can create the table with the following code:
drop table if exists schema.pl_address_cnt;
create table schema.pl_address_cnt (
id serial,
address_id int);
insert into schema.pl_address_cnt(address_id) values
(100), (101), (100), (101), (100), (125), (128), (200), (200), (100);
My task is to count for each id how many other ids (thus -1) have the same address_id. I've come up with a solution that turns out to be quite expensive (explain) on the original dataset. I wonder whether my solution can be somehow optimised.
with tmp_table as (select address_id
, count(distinct id) as id_count
from schema.pl_address_cnt
group by address_id
)
select id
, id_count - 1
from schema.pl_address_cnt as pac
left join tmp_table as tt on tt.address_id=pac.address_id;
You can try to omit the CTE and do a self left join on common address but different ID and then aggregate this.
SELECT pac1.id,
count(pac2.id)
FROM pl_address_cnt pac1
LEFT JOIN pl_address_cnt pac2
ON pac1.address_id = pac2.address_id
AND pac1.id <> pac2.id
GROUP BY pac1.id
ORDER BY pac1.id;
For performance you can try indexes on (address_id, id) and (id).

Selecting one specific data row (required), and 3 others (specific data row must be included)

I need to select a specific row and 2 other rows that is not that specific row (a total of 3). The specific row must always be included in the 3 results. How should I go about it? I think it can be done with a UNION ALL, but do I have another choice? Thanks all! :)
Here are my scripts to create the sample tables:
create table users (
user_id serial primary key,
user_name varchar(20) not null
);
create table result_table1 (
result_id serial primary key,
user_id int4 references users(user_id),
result_1 int4 not null
);
create table result_table2 (
result_id serial primary key,
user_id int4 references users(user_id),
result_2 int4 not null
);
insert into users (user_name) values ('Kevin'),('John'),('Batman'),('Someguy');
insert into result_table1 (user_id, result_1) values (1, 20),(2, 40),(3, 70),(4, 42);
insert into result_table2 (user_id, result_2) values (1, 4),(2, 3),(3, 7),(4, 5);
Here is my UNION query:
SELECT result_table1.user_id,
result_1,
result_2
FROM result_table1
INNER JOIN (
SELECT user_id
FROM users
) users
ON users.user_id = result_table1.user_id
INNER JOIN (
SELECT result_table2.user_id,
result_2
FROM result_table2
) result_table2
ON result_table2.user_id = result_table1.user_id
WHERE users.user_id = 1
UNION ALL
SELECT result_table1.user_id,
result_1,
result_2
FROM result_table1
INNER JOIN (
SELECT user_id
FROM users
) users
ON users.user_id = result_table1.user_id
INNER JOIN (
SELECT result_table2.user_id,
result_2
FROM result_table2
) result_table2
ON result_table2.user_id = result_table1.user_id
WHERE users.user_id != 1
LIMIT 3;
Are there any options other than a UNION? The query works and does what I want for now, but will it always include user_id = 1 if I had a larger set of rows (assume that user_id = 1 will always be there)? :(
Thank you all! :)

Copy content in TSQL

I need to copy content from one table to itself and related tables... Let me schematize the problem. Let's say I have two tables:
Order
OrderID : int
CustomerID : int
OrderName : nvarchar(32)
OrderItem
OrderItemID : int
OrderID : int
Quantity : int
With the PK being autoincremental.
Let's say I want to duplicate the content of one customer to another. How do I do that efficiently?
The problem are the PKs. I would need to map the values of OrderIDs from the original set of data to the copy in order to create proper references in OrderItem. If I just select-Insert, I won't be able to create that map.
Suggestions?
For duplicating one parent and many children with identities as the keys, I think the OUTPUT clause can make things pretty clean (SqlFiddle here):
-- Make a duplicate of parent 1, including children
-- Setup some test data
create table Parents (
ID int not null primary key identity
, Col1 varchar(10) not null
, Col2 varchar(10) not null
)
insert into Parents (Col1, Col2) select 'A', 'B'
insert into Parents (Col1, Col2) select 'C', 'D'
insert into Parents (Col1, Col2) select 'E', 'F'
create table Children (
ID int not null primary key identity
, ParentID int not null references Parents (ID)
, Col1 varchar(10) not null
, Col2 varchar(10) not null
)
insert into Children (ParentID, Col1, Col2) select 1, 'g', 'h'
insert into Children (ParentID, Col1, Col2) select 1, 'i', 'j'
insert into Children (ParentID, Col1, Col2) select 2, 'k', 'l'
insert into Children (ParentID, Col1, Col2) select 3, 'm', 'n'
-- Get one parent to copy
declare #oldID int = 1
-- Create a place to store new ParentID
declare #newID table (
ID int not null primary key
)
-- Create new parent
insert into Parents (Col1, Col2)
output inserted.ID into #newID -- Capturing the new ParentID
select Col1, Col2
from Parents
where ID = #oldID -- Only one parent
-- Create new children using the new ParentID
insert into Children (ParentID, Col1, Col2)
select n.ID, c.Col1, c.Col2
from Children c
cross join #newID n
where c.ParentID = #oldID -- Only one parent
-- Show some output
select * from Parents
select * from Children
Do you have to have the primary keys from table A as primaries in Table B? If not you can do a select statement with an insert into. Primary Key's are usually int's that start from an ever increasing seed (identity). Going around this and declaring an insert of this same data problematically has the disadvantage of someone thinking this is a distinct key set on this table and not a 'relationship' or foreign key value.
You can Select Primary Key's for inserts into other tables, just not themselves.... UNLESS you set the 'identity insert on' hint. Do not do this unless you know what this does as you can create more problems than it's worth if you don't understand the ramifications.
I would just do the ole:
insert into TableB
select *
from TableA
where (criteria)
Simple example (This assumes SQL Server 2008 or higher). My bad I did not see you did not list TSQL framework. Not sure if this will run on Oracle or MySql.
declare #Order Table ( OrderID int identity primary key, person varchar(8));
insert into #Order values ('Brett'),('John'),('Peter');
declare #OrderItem Table (orderItemID int identity primary key, OrderID int, OrderInfo varchar(16));
insert into #OrderItem
select
OrderID -- I can insert a primary key just fine
, person + 'Stuff'
from #Order
select *
from #Order
Select *
from #OrderItem
Add an extra helper column to Order called OldOrderID
Copy all the Order's from the #OldCustomerID to the #NewCustomerID
Copy all of the OrderItems using the OldOrderID column to help make the relation
Remove the extra helper column from Order
ALTER TABLE Order ADD OldOrderID INT NULL
INSERT INTO Order (CustomerID, OrderName, OldOrderID)
SELECT #NewCustomerID, OrderName, OrderID
FROM Order
WHERE CustomerID = #OldCustomerID
INSERT INTO OrderItem (OrderID, Quantity)
SELECT o.OrderID, i.Quantity
FROM Order o INNER JOIN OrderItem i ON o.OldOrderID = i.OrderID
WHERE o.CustomerID = #NewCustomerID
UPDATE Order SET OldOrderID = null WHERE OldOrderID IS NOT NULL
ALTER TABLE Order DROP COLUMN OldOrderID
IF the OrderName is unique per customer, you could simply do:
INSERT INTO [Order] ([CustomerID], [OrderName])
SELECT
2 AS [CustomerID],
[OrderName]
FROM [Order]
WHERE [CustomerID] = 1
INSERT INTO [OrderItem] ([OrderID], [Quantity])
SELECT
[o2].[OrderID],
[oi1].[Quantity]
FROM [OrderItem] [oi1]
INNER JOIN [Order] [o1] ON [oi1].[OrderID] = [o1].[OrderID]
INNER JOIN [Order] [o2] ON [o1].[OrderName] = [o2].[OrderName]
WHERE [o1].[CustomerID] = 1 AND [o2].[CustomerID] = 2
Otherwise, you will have to use a temporary table or alter the existing Order table like #LastCoder suggested.