I've been reading all of the transpose rows to columns links on the whole of Stack, but I can't quite get the code in those to work with my situation.
I have a device table
deviceID
DeviceName
I have an attribute table
AttributeID
AttributeName
and then I have a many to many mapping table of devices to attributes
DeviceId
AttributeID
AttributeValue
so let's say one of the attributes is the device's name and another is its IP address. When I make a query joining these 3 tables I'll get 2 rows for a given device
deviceID attributeName attributeValue
2 name Server1
2 IPAddress 10.1.1.1
What I need is a view that flattens it back out so I have an output that looks like this:
deviceid name IPAddress
2 Server1 10.1.1.1
Sample Code please - I just was not able to get an unpivot to work
Thank you,
CREATE TABLE #device
(
deviceID INT NOT NULL
, DeviceName NVARCHAR(100) NOT NULL
);
CREATE TABLE #attribute
(
AttributeID INT NOT NULL
, AttributeName NVARCHAR(100) NOT NULL
);
CREATE TABLE #bridgeDeviceAttribute
(
DeviceId INT NOT NULL
, AttributeID INT NOT NULL
, AttributeValue NVARCHAR(100) NOT NULL
);
INSERT INTO #device (deviceID, DeviceName) VALUES (2, N'MyDevice');
INSERT INTO #attribute
(
AttributeID
, AttributeName
)
VALUES
(1, N'name')
, (2, N'IPAddress');
INSERT INTO #bridgeDeviceAttribute
(
DeviceId
, AttributeID
, AttributeValue
)
VALUES
(2, 1, N'Server1')
, (2, 2, N'10.1.1.1');
SELECT
pvt.deviceID
, pvt.name
, pvt.IPAddress
FROM (
SELECT
d.deviceID
, a.AttributeName
, bda.AttributeValue
FROM #bridgeDeviceAttribute bda
JOIN #attribute a
ON a.AttributeID = bda.AttributeID
JOIN #device d
ON d.deviceID = bda.DeviceId
) t
PIVOT (
MIN(AttributeValue)
FOR AttributeName IN (name, IPAddress)
) pvt;
Results look like this:
Related
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;
I'm trying to construct an object for use from my postgres backend. The tables in question look something like this:
We have some Things that essentially act as rows for a matrix where the columns are Field_Columns. Field_Values are filled cells.
Create Table Platform_User (
serial id PRIMARY KEY
)
Create Table Things (
serial id PRIMARY KEY,
INTEGER user_id REFERENCES Platform_User(id)
)
Create Table Field_Columns (
serial id PRIMARY KEY,
TEXT name,
)
Create Table Field_Values (
INTEGER field_column_id REFERENCES Field_Columns(id),
INTEGER thing_id REFERENCES Things(id)
TEXT content,
PRIMARY_KEY(field_column_id, thing_id)
)
This would be simple if I were trying to load just the Field_Values for a single Thing as JSON, which would look like this:
SELECT JSONB_OBJECT(
ARRAY(
SELECT name
FROM Field_Columns
ORDER BY Field_Columns.id
),
ARRAY(
SELECT Field_Values.content
FROM Fields_Columns
LEFT JOIN Field_Values ON Field_Values.field_column_id = Field_Columns.id
AND Field_Values.thing_id = Things.id
ORDER BY Field_Columns.id)
)
)
FROM Things
WHERE Thing.id = $1
however, I'd like to construct the JSON object to look like this when returned. I want to get an object of all the Fields:Field_Values objects for the Things that a user owns
{
14:
{
'first field':'asdf',
'other field':''
}
25:
{
'first field':'qwer',
'other field':'dfgdsfg'
}
43:
{
'first field':'',
'other field':''
}
}
My efforts to construct this query look like this, but I'm running into the problem where the JSONB object function doesn't want to construct an object where the value of the field is an object itself
SELECT (
JSONB_OBJECT(
ARRAY(SELECT Things.id::TEXT
FROM Things
WHERE Things.user_id = $2
ORDER BY Things.id
),
ARRAY(SELECT JSONB_OBJECT(
ARRAY(
SELECT name
FROM Field_Columns
ORDER BY Field_Columns.id),
ARRAY(
SELECT Field_Values.content
FROM Field_Columns
LEFT JOIN Field_Values ON Field_Values.field_column_Id = Field_Columns.id
AND Field_Values.thing_id = Things.id
ORDER BY Field_Columns.id)
)
FROM Things
WHERE Things.user_id = $2
ORDER BY Things.id
)
)
) AS thing_fields
The specific error I get is function jsonb_object(text[], jsonb[]) does not exist. Is there a way to do this that doesn't involve copious text conversions and nonsense like that? Or will I just need to abandon trying to sort my data in the query and do it in my code instead.
Your DDL scripts are syntactically incorrect so I created these for you:
create table platform_users (
id int8 PRIMARY KEY
);
create table things (
id int8 PRIMARY KEY,
user_id int8 REFERENCES platform_users(id)
);
create table field_columns (
id int8 PRIMARY KEY,
name text
);
create table field_values (
field_column_id int8 REFERENCES field_columns(id),
thing_id int8 REFERENCES things(id),
content text,
PRIMARY KEY(field_column_id, thing_id)
);
I also created some scripts to populate the db:
insert into platform_users(id) values (1);
insert into platform_users(id) values (2);
insert into platform_users(id) values (3);
insert into platform_users(id) values (4);
insert into platform_users(id) values (5);
insert into things(id, user_id) values(1, 1);
insert into things(id, user_id) values(2, 1);
insert into things(id, user_id) values(3, 2);
insert into things(id, user_id) values(4, 2);
insert into field_columns(id, name) values(1, 'col1');
insert into field_columns(id, name) values(2, 'col2');
insert into field_values(field_column_id, thing_id, content) values(1, 1, 'thing1 val1');
insert into field_values(field_column_id, thing_id, content) values(2, 1, 'thing1 val2');
insert into field_values(field_column_id, thing_id, content) values(1, 2, 'thing2 val1');
insert into field_values(field_column_id, thing_id, content) values(2, 2, 'thing2 val2');
Please include such scripts next time when you ask for help, and make sure that your scripts are correct. This will reduce the work needed to answer your question.
You can get your jsonb value by aggregating the key value pairs with jsonb_object_agg
select
t.id,
jsonb_object_agg(fc.name, fv.content)
from
things t inner join
field_values fv on fv.thing_id = t.id inner join
field_columns fc on fv.field_column_id = fc.id
group by 1
The results looking like this:
thing_id;jsonb_value
1;"{"col1": "thing1 val1", "col2": "thing1 val2"}"
2;"{"col1": "thing2 val1", "col2": "thing2 val2"}"
How can I use default constraints, triggers, or some other mechanism to automatically insert multiple successive values from a sequence into multiple columns on the same row of a table?
A standard use of a sequence in SQL Server is to combine it with default constraints on multiple tables to essentially get a cross-table identity. See for example the section "C. Using a Sequence Number in Multiple Tables" in the Microsoft documentation article "Sequence Numbers".
This works great if you only want to get a single value from the sequence for each row inserted. But sometimes I want to get multiple successive values. So theoretically I would create a sequence and table like this:
CREATE SEQUENCE DocumentationIDs;
CREATE TABLE Product
(
ProductID BIGINT NOT NULL IDENTITY(1, 1) PRIMARY KEY
, ProductName NVARCHAR(100) NOT NULL
, MarketingDocumentationID BIGINT NOT NULL DEFAULT ( NEXT VALUE FOR DocumentationIDs )
, TechnicalDocumentationID BIGINT NOT NULL DEFAULT ( NEXT VALUE FOR DocumentationIDs )
, InternalDocumentationID BIGINT NOT NULL DEFAULT ( NEXT VALUE FOR DocumentationIDs )
);
Unfortunately this will insert the same value in all three columns. This is by design:
If there are multiple instances of the NEXT VALUE FOR function specifying the same sequence generator within a single Transact-SQL statement, all those instances return the same value for a given row processed by that Transact-SQL statement. This behavior is consistent with the ANSI standard.
Increment by hack
The only suggestion I could find online was to use a hack where you have the sequence increment by the number of columns you need to insert (three in my contrived example) and manually add to the NEXT VALUE FOR function in the default constraint:
CREATE SEQUENCE DocumentationIDs START WITH 1 INCREMENT BY 3;
CREATE TABLE Product
(
ProductID BIGINT NOT NULL IDENTITY(1, 1) PRIMARY KEY
, ProductName NVARCHAR(100) NOT NULL
, MarketingDocumentationID BIGINT NOT NULL DEFAULT ( NEXT VALUE FOR DocumentationIDs )
, TechnicalDocumentationID BIGINT NOT NULL DEFAULT ( ( NEXT VALUE FOR DocumentationIDs ) + 1 )
, InternalDocumentationID BIGINT NOT NULL DEFAULT ( ( NEXT VALUE FOR DocumentationIDs ) + 2 )
)
This does not work for me because not all tables using my sequence require the same number of values.
One possible way using AFTER INSERT trigger is following.
Table definition need to be changed slighlty (DocumentationID columns should be defaulted to 0, or allowed to be nullable):
CREATE TABLE Product
(
ProductID BIGINT NOT NULL IDENTITY(1, 1)
, ProductName NVARCHAR(100) NOT NULL
, MarketingDocumentationID BIGINT NOT NULL CONSTRAINT DF_Product_1 DEFAULT (0)
, TechnicalDocumentationID BIGINT NOT NULL CONSTRAINT DF_Product_2 DEFAULT (0)
, InternalDocumentationID BIGINT NOT NULL CONSTRAINT DF_Product_3 DEFAULT (0)
, CONSTRAINT PK_Product PRIMARY KEY (ProductID)
);
And the trigger doing the job is following:
CREATE TRIGGER Product_AfterInsert ON Product
AFTER INSERT
AS
BEGIN
SET NOCOUNT ON;
IF NOT EXISTS (SELECT 1 FROM INSERTED)
RETURN;
CREATE TABLE #DocIDs
(
ProductID BIGINT NOT NULL
, Num INT NOT NULL
, DocID BIGINT NOT NULL
, PRIMARY KEY (ProductID, Num)
);
INSERT INTO #DocIDs (ProductID, Num, DocID)
SELECT
i.ProductID
, r.n
, NEXT VALUE FOR DocumentationIDs OVER (ORDER BY i.ProductID, r.n)
FROM INSERTED i
CROSS APPLY (VALUES (1), (2), (3)) r(n)
;
WITH Docs (ProductID, MarketingDocID, TechnicalDocID, InternalDocID)
AS (
SELECT ProductID, [1], [2], [3]
FROM #DocIDs d
PIVOT (MAX(DocID) FOR Num IN ([1], [2], [3])) pvt
)
UPDATE p
SET
p.MarketingDocumentationID = d.MarketingDocID
, p.TechnicalDocumentationID = d.TechnicalDocID
, p.InternalDocumentationID = d.InternalDocID
FROM Product p
JOIN Docs d ON d.ProductID = p.ProductID
;
END
I want to select from an enumaration that is not in database.
E.g. SELECT id FROM my_table returns values like 1, 2, 3
I want to display 1 -> 'chocolate', 2 -> 'coconut', 3 -> 'pizza' etc. SELECT CASE works but is too complicated and hard to overview for many values. I think of something like
SELECT id, array['chocolate','coconut','pizza'][id] FROM my_table
But I couldn't succeed with arrays. Is there an easy solution? So this is a simple query, not a plpgsql script or something like that.
with food (fid, name) as (
values
(1, 'chocolate'),
(2, 'coconut'),
(3, 'pizza')
)
select t.id, f.name
from my_table t
join food f on f.fid = t.id;
or without a CTE (but using the same idea):
select t.id, f.name
from my_table t
join (
values
(1, 'chocolate'),
(2, 'coconut'),
(3, 'pizza')
) f (fid, name) on f.fid = t.id;
This is the correct syntax:
SELECT id, (array['chocolate','coconut','pizza'])[id] FROM my_table
But you should create a referenced table with those values.
What about creating another table that enumerate all cases, and do join ?
CREATE TABLE table_case
(
case_id bigserial NOT NULL,
case_name character varying,
CONSTRAINT table_case_pkey PRIMARY KEY (case_id)
)
WITH (
OIDS=FALSE
);
and when you select from your table:
SELECT id, case_name FROM my_table
inner join table_case on case_id=my_table_id;
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.