Here are the tables:
CREATE TABLE [dbo].[Classes](
[ClassId] [int] NOT NULL,
[ClassName] [nvarchar](50) NOT NULL,
CONSTRAINT [PK_Classes] PRIMARY KEY CLUSTERED
(
[ClassId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[Students](
[StudentId] [int] NOT NULL,
[ClassId] [int] NOT NULL,
CONSTRAINT [PK_Students] PRIMARY KEY CLUSTERED
(
[StudentId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Students] WITH CHECK ADD CONSTRAINT [FK_Students_Classes] FOREIGN KEY([ClassId])
REFERENCES [dbo].[Classes] ([ClassId])
GO
ALTER TABLE [dbo].[Students] CHECK CONSTRAINT [FK_Students_Classes]
GO
I want to get list of class, and each class - the number of student which belong to each class.
How can I do this?
You need to do this -
SELECT C.ClassId, C.ClassName, count(S.StudentId) AS studentCount
FROM CLASSES C LEFT JOIN STUDENTS S ON (C.ClassId=S.ClassId)
GROUP BY C.ClassId, C.ClassName
You mean something like this?
SELECT C.[ClassName], COUNT(*) AS 'Number of Students'
FROM [dbo].[Classes] AS C
INNER JOIN [dbo].[Students] AS S ON S.[ClassId] = C.[ClassId]
GROUP BY C.[ClassName]
Without having to add the group by clause, you can do the following:
Create a function to get the students count:
go
CREATE FUNCTION [dbo].GetStudentsCountByClass(#classId int) RETURNS INT
AS BEGIN
declare #count as int
select #count = count(*) from STUDENTS
where ClassId = #classId
RETURN #count
END
then use it in your select statement
SELECT * , dbo.GetStudentsCountByClass(ClassId) AS StudentsCount
FROM Classes
select c.ClassId,C.ClassName,COUNT(*) [Number of students]
from Classes C,Students S
where c.ClassId=S.ClassId
group by C.ClassId,C.ClassName
SELECT class.ClassId, count(student .StudentId) AS studentCount
FROM dbo.CLASSES class LEFT JOIN dbo.STUDENTS student ON (class.ClassId=student.ClassId)
GROUP BY class.ClassId
Related
Let's say I have 3 tables: users, customattributes, and customattributevalues. End user can add custom attributes by selecting a name and type for the attribute, and the edit the values for any user.
Here are my users:
id
firstname
lastname
active
datecreated
username
email
3
Ellen
Ripley
1
3/25/2235
78439
Rip8439#Weyland-Yutani.com
5
Johnny
Rico
1
4/16/2675
Roughneck31
RicoJ31#Roughnecks.com
customattributes (can be added to anytime)
id
fullname
uniquename
type
1
Hire Date
hiredate
date
2
Employee ID
eeid
int
3
Supervisor
supervisor
nvarchar(50)
4
Assigned Ship
assignedship
nvarchar(50)
5
Job Title
jobtitle
nvarchar(50)
type I currently have as sysname datatype.
customattributevalues (can be edited anytime)
id
attributeid
userid
value
1
1
3
2335-03-25
2
2
3
78439
3
3
3
Burke, Carter
4
4
3
Sulaco
5
5
3
Consultant
6
1
5
2675-04-16
7
2
5
78440
8
3
5
LT Rasczak
9
4
5
Rodger Young
10
5
5
Private
value I currently have as sql_variant datatype
So here is my question: how can I create a report that shows all employees and their attributes, 1 line per employee, without knowing how many custom attributes there are --and-- crucially, I want to explicitly convert each column to the correct data type
Desired output:
firstname
lastname
datecreated
username
email
Hire Date
Employee ID
Supervisor
Assigned Ship
Job Title
Ellen
Ripley
2235-03-25
78439
Rip8439#Weyland-Yutani.com
2335-03-25
78439
Burke, Carter
Sulaco
Consultant
Johnnie
Rico
2675-04-16
Roughneck31
RicoJ31#Roughnecks.com
2675-04-16
78440
LT Rasczak
Rodger Young
Private
I've already learned to do the dynamic column headers using dynamic queries, but it is the type conversion that is escaping me.
I'm adapting this solution for custom fields, but the limitation to this solution is you have to know each custom field to make the type conversion.
Here is what I've tried. I got the correct output, except for the type conversions.
Query:
DECLARE #columns NVARCHAR(MAX) = '';
DECLARE #sqlcmd NVARCHAR(MAX) = '';
SELECT #columns += QUOTENAME(fullname) + ','
FROM customattributesx ca
ORDER BY ca.id;
SET #columns = LEFT(#columns, LEN(#columns) - 1);
--PRINT #columns;
SET #sqlcmd = '
SELECT * FROM (
SELECT userid
,firstname
,lastname
,datecreated
,username
,email
,fullname
,value
FROM (
SELECT u.id as userid
,u.firstname
,u.lastname
,u.datecreated
,u.username
,u.email
,ca.id
,ca.fullname as fullname
,ca.uniquename
,ca.type
,cav.value as value
FROM dbo.users u
CROSS JOIN customattributesx ca
INNER JOIN customattributevaluesx cav
ON cav.attributeid = ca.id AND cav.userid = u.id
--ORDER BY u.id asc, ca.id asc
) t1
) t2
PIVOT (
MIN(value)
FOR fullname IN ('+#columns+')
) as pivottable
';
--print #sqlcmd
EXECUTE (#sqlcmd)
Create Tables:
USE [CTMS]
GO
/****** Object: Table [dbo].[users] Script Date: 11/24/2021 9:29:16 AM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[users](
[id] [int] IDENTITY(1,1) NOT NULL,
[firstname] [nvarchar](max) NULL,
[lastname] [nvarchar](max) NULL,
[active] [bit] NOT NULL,
[datecreated] [datetime2](7) NOT NULL,
[username] [nvarchar](256) NULL,
[email] [nvarchar](256) NULL,
[emailconfirmed] [bit] NOT NULL,
[passwordhash] [nvarchar](max) NULL,
[twofactorenabled] [bit] NOT NULL,
[lockoutend] [datetimeoffset](7) NULL,
[eockoutenabled] [bit] NOT NULL,
[accessfailedcount] [int] NOT NULL,
[qrcode] [nvarchar](50) NULL,
CONSTRAINT [PK_id] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY],
CONSTRAINT [uk_email] UNIQUE NONCLUSTERED
(
[email] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY],
CONSTRAINT [uk_qrcode] UNIQUE NONCLUSTERED
(
[qrcode] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY],
CONSTRAINT [uk_username] UNIQUE NONCLUSTERED
(
[username] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO
ALTER TABLE [dbo].[users] ADD DEFAULT (getutcdate()) FOR [datecreated]
GO
USE [CTMS]
GO
/****** Object: Table [dbo].[customattributesx] Script Date: 11/24/2021 9:31:09 AM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[customattributesx](
[id] [smallint] IDENTITY(1,1) NOT NULL,
[fullname] [nvarchar](50) NOT NULL,
[uniquename] [nvarchar](50) NOT NULL,
[type] [sysname] NOT NULL,
CONSTRAINT [PK_customattributesx] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY],
CONSTRAINT [uk1_customattributesx] UNIQUE NONCLUSTERED
(
[uniquename] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
GO
USE [CTMS]
GO
/****** Object: Table [dbo].[customattributevaluesx] Script Date: 11/24/2021 9:31:27 AM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[customattributevaluesx](
[id] [int] IDENTITY(1,1) NOT NULL,
[attributeid] [smallint] NOT NULL,
[userid] [int] NOT NULL,
[value] [sql_variant] NOT NULL,
CONSTRAINT [PK_customattributevaluesx] PRIMARY KEY CLUSTERED
(
[id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY],
CONSTRAINT [uk1_customattributevaluesx] UNIQUE NONCLUSTERED
(
[attributeid] ASC,
[userid] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[customattributevaluesx] WITH CHECK ADD CONSTRAINT [fk1_customattributesvaluesx] FOREIGN KEY([attributeid])
REFERENCES [dbo].[customattributesx] ([id])
GO
ALTER TABLE [dbo].[customattributevaluesx] CHECK CONSTRAINT [fk1_customattributesvaluesx]
GO
ALTER TABLE [dbo].[customattributevaluesx] WITH CHECK ADD CONSTRAINT [fk2_customattributesvaluesx] FOREIGN KEY([userid])
REFERENCES [dbo].[users] ([id])
GO
ALTER TABLE [dbo].[customattributevaluesx] CHECK CONSTRAINT [fk2_customattributesvaluesx]
GO
If you must convert the datatype (could really be a presentation layer thing), then a dynamic conditional aggregation should do the trick.
Example
Declare #SQL nvarchar(max) ='
Select U.*' +
(
Select concat(',',quotename(fullname),'=max(case when attributeid=',id,' then try_convert(',type,',value) end)')
From customattributes
For XML Path ('')
)+'
From users U
Join customattributesvalues V on U.ID=V.userid
Group By U.ID
,U.FirstName
,U.LastName
,U.active
,U.datecreated
,U.username
,U.email
'
--print #SQL
Exec(#SQL)
Results
The Generated SQL Looks Like This
Select U.*
,[Hire Date]=max(case when attributeid=1 then try_convert(date,value) end)
,[Employee ID]=max(case when attributeid=2 then try_convert(int,value) end)
,[Supervisor]=max(case when attributeid=3 then try_convert(nvarchar(50),value) end)
,[Assigned Ship]=max(case when attributeid=4 then try_convert(nvarchar(50),value) end)
,[Job Title]=max(case when attributeid=5 then try_convert(nvarchar(50),value) end)
From #users U
Join #customattributesvalues V on U.ID=V.userid
Group By U.ID
,U.FirstName
,U.LastName
,U.active
,U.datecreated
,U.username
,U.email
SQL_VARIANT can be cast to a destination data type.
Modify part of the dynamic query where you generate column list, to generate two lists. One list is for PIVOT part and the other for SELECT part where you cast you data types.
Example is based on the article you refer to in your question:
DECLARE #PivotList NVARCHAR( MAX )
DECLARE #SelectList NVARCHAR( MAX )
SELECT #SelectList = NULL, #PivotList = NULL
-- Column list with CAST e.g. CAST( eeid AS INT ) AS eeid
-- Data types come from your customattributes table
SELECT #SelectList = COALESCE( #SelectList + ',','') + 'CAST( ' + uniquename + ' AS [type] ) AS ' + uniquename,
-- Just a column list that goes into PIVOT operator
#PivotList = COALESCE( #PivotList + ',','') + uniquename
-- Your tables for attribute values and attribute type definitions
FROM customattributes AS ca
DECLARE #SQLQuery NVARCHAR(MAX)
SET #SQLQuery =
'SELECT StudID , '+#SelectList+'
FROM
( SELECT SM.StudID, S.SubjectName, SM.Score
FROM StudentMarks SM
INNER JOIN Subjects S
ON Sm.SubjectID = S.SubjectID
) AS tbl
PIVOT
( Sum(Score)
FOR SubjectName IN ('+#PivotList+') ) as pvt'
EXEC(#SQLQuery)
I am currently trying to join 3 tables. The main table is company, if there is 3 companies and 2 roles exists in the role table I want the output to be like this:
Company1, Role 1, <iduser>
Company1, Role 2, <iduser>
Company2, Role 1, <iduser>
Company2, Role 2, <iduser>
Company3, Role 1, <iduser>
Company3, Role 2, <iduser>
For each role there must be a row for a company. If no user is linked to a role and company then it should just show: Companyname, Rolename, null
Database schema:
CREATE TABLE [dbo].[role](
[idrole] [int] IDENTITY(1,1) NOT NULL,
[name] [nchar](100) NOT NULL,
CONSTRAINT [PK_role] PRIMARY KEY CLUSTERED
(
[idrole] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[company](
[idcompany] [int] IDENTITY(1,1) NOT NULL,
[name] [nchar](100) NOT NULL,
CONSTRAINT [PK_company] PRIMARY KEY CLUSTERED
(
[idcompany] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[user](
[iduser] [int] IDENTITY(1,1) NOT NULL,
[name] [nchar](100) NOT NULL,
[idcompany] [int] NOT NULL,
[idrole] [int] NULL,
CONSTRAINT [PK_user] PRIMARY KEY CLUSTERED
(
[iduser] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[user] WITH CHECK ADD CONSTRAINT [FK_user_company] FOREIGN KEY([idcompany])
REFERENCES [dbo].[company] ([idcompany])
GO
ALTER TABLE [dbo].[user] CHECK CONSTRAINT [FK_user_company]
GO
ALTER TABLE [dbo].[user] WITH CHECK ADD CONSTRAINT [FK_user_role] FOREIGN KEY([idrole])
REFERENCES [dbo].[role] ([idrole])
GO
ALTER TABLE [dbo].[user] CHECK CONSTRAINT [FK_user_role]
GO
Test data script:
INSERT INTO [test].[dbo].[company]
VALUES ('Company 1')
INSERT INTO [test].[dbo].[company]
VALUES ('Company 2')
INSERT INTO [test].[dbo].[company]
VALUES ('Company 3')
INSERT INTO [test].[dbo].[role]
VALUES ('Role 1')
INSERT INTO [test].[dbo].[role]
VALUES ('Role 2')
Attempt:
SELECT roles.name, users.iduser
FROM [test].[dbo].[role] roles
JOIN [test].[dbo].[user] users ON roles.idrole = users.idrole
JOIN [test].[dbo].[company] company ON company.idcompany = users.idcompany
Please advise what approach I can use to achieve this
Given you don't have a relationship between a Role and a Company, I assume you want every combination of Role/Company, which is where you use a CROSS JOIN.
Then you would LEFT JOIN your User table on since you want to return null if a user doesn't exist for a given Company-Role.
SELECT C.[name], R.[name], U.iduser
FROM [test].[dbo].[role] R
CROSS JOIN [test].[dbo].[company] C
LEFT JOIN [test].[dbo].[user] U ON U.idrole = R.idrole and U.idcompany = C.idcompany
ORDER BY C.[name], R.[name], U.iduser;
Note the use of shorter aliases for clarity.
I think we need to apply a cross join of the 2 tables the Company and Role tables, afterwards join with the users
select * from (
select idcompany, b.name as coname, a.name, a.idrole
from company b
cross join
(select idrole, name from role) a
) c
left join dbuser d on c.idcompany = d.idrole
order by c.coname, c.name
We have a trigger that we are trying to update so that when a record is updated, the trigger will update a second table. When we activate the change, we get an error
Violation of PRIMARY KEY contstraint 'KPRIMARY_SO_SalesOrderHeader". Cannot insert duplicate key in object 'dbo.SO_SalesOrderHeader". The duplicate key is XXXXXX.
I'm really confused by this because I don't see in the trigger where we are trying to insert a key.
ALTER Trigger [dbo].[SO_SALESORDERHEADER_onOrderChange]
ON [dbo].[SO_SalesOrderHeader]
FOR INSERT, UPDATE
AS
SET NOCOUNT ON;
--+
INSERT INTO dbo.OrderUpdateQueue (SourceId, OrderNumber, Action)
SELECT DISTINCT
N'SO', Inserted.SALESORDERNO, N'U'
FROM
Inserted
LEFT JOIN
dbo.OrderUpdateQueue ON (Inserted.SALESORDERNO = OrderUpdateQueue.OrderNumber)
AND (OrderUpdateQueue.SourceID = N'SO')
AND (OrderUpdateQueue.Action = N'U')
WHERE
(OrderUpdateQueue.[Key] IS NULL)
AND (Inserted.SALESORDERNO IS NOT NULL);
--+ New Trigger Stuff
UPDATE MO
SET MO.[ShipDate] = I.ShipExpireDate
FROM [BACKEND_db].[dbo].[Order] MO
INNER JOIN Inserted I ON I.SalesOrderNo = MO.OrderId
WHERE MO.ShipDate <> I.ShipExpireDate;
CREATE TABLE [dbo].[SO_SalesOrderHeader](
[SalesOrderNo] [varchar](7) NOT NULL
CONSTRAINT [KPRIMARY_SO_SalesOrderHeader] PRIMARY KEY CLUSTERED
(
[SalesOrderNo] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,
ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[OrderUpdateQueue](
[Key] [int] IDENTITY(1,1) NOT NULL,
[SourceId] [nvarchar](50) NOT NULL,
[OrderNumber] [nvarchar](50) NOT NULL,
[Action] [nchar](1) NOT NULL,
CONSTRAINT [PK_OrderUpdateQueue] PRIMARY KEY CLUSTERED
(
[Key] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,
ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
USE [BACKEND_db]
CREATE TABLE [dbo].[Order](
[Key] [int] IDENTITY(1,1) NOT NULL,
[OrderId] [nvarchar](10) NULL,
[ShipDate] [datetime] NULL
CONSTRAINT [PK_MasOrder] PRIMARY KEY CLUSTERED
(
[Key] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,
ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]
GO
How you do not post the schema of OrderUpdateQueue table, I believe the pk is the OrderNumber field. You can try to change your trigger to:
ALTER Trigger [dbo].[SO_SALESORDERHEADER_onOrderChange]
ON [dbo].[SO_SalesOrderHeader]
FOR INSERT, UPDATE
AS
SET NOCOUNT ON;
--+
INSERT INTO dbo.OrderUpdateQueue (SourceId, OrderNumber, Action)
SELECT DISTINCT
N'SO', Inserted.SALESORDERNO, N'U'
FROM
Inserted
WHERE not exists (SELECT 1 FROM dbo.OrderUpdateQueue where Inserted.SALESORDERNO = OrderUpdateQueue.OrderNumber)
UPDATE MO
SET MO.[ShipDate] = I.ShipExpireDate
FROM [BACKEND_db].[dbo].[Order] MO
INNER JOIN Inserted I ON I.SalesOrderNo = MO.OrderId
WHERE MO.ShipDate <> I.ShipExpireDate;
What is the optimal select according to you?
select #MailTo=ISNULL((select data from filedata where descid=3104 and DataId=evt04) ,'')
from event_21
where evtid=#nFileId
or
select #MailTo=ISNULL(data ,'')
from event_21
innerjoin filedata on event_21.evt04=filedata.dataid
where descid=3104
and evtid=#nFileId
Obviously "join" is faster than "inline select query". I have tested with 1000 rows. You can also test. here is the sample test code.
CREATE TABLE [dbo].[tableA](
[Id] [int] IDENTITY(1,1) NOT NULL,
[Name] [nvarchar](100) NOT NULL,
CONSTRAINT [PK_tableA] PRIMARY KEY CLUSTERED
(
[Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[tableB](
[RowId] [int] IDENTITY(1,1) NOT NULL,
[Id] [int] NOT NULL,
[Designation] [nvarchar](100) NULL,
CONSTRAINT [PK_tableB] PRIMARY KEY CLUSTERED
(
[RowId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
Declare #Min Int = 1
,#Max Int = 1000
While (#Min <= #Max)
Begin
Insert Into tableA(Name)
Select 'Name would be the name of - ' + Cast(#Min As Nvarchar(10))
Insert Into tableB(Id,Designation)
Select #Min
,'Desig could be the name of - Name' + Cast(#Min As Nvarchar(10))
Select #Min = #Min + 1
End
First look # inline select query
-- inline query
Select a.Id
,a.Name
,(Select Designation From tableB As b Where b.Id = a.Id) As Designation
From tableA As a With (Nolock)
output:
Execution Plan:
now the Join query :-
---- join
Select a.Id
,a.Name
,b.Designation
From tableA As a With (Nolock)
Join tableB As b On a.Id = b.Id
execution plan for join query :-
you can see the clear difference.
I wish to migrate some data from a single table into these new THREE tables.
Here's my destination schema:
Notice that I need to insert into the first Location table .. grab the SCOPE_IDENTITY() .. then insert the rows into the Boundary and Country tables.
The SCOPE_IDENTITY() is killing me :( meaning, I can only see a way to do this via CURSORS. Is there a better alternative?
UPDATE
Here's the scripts for the DB Schema....
Location
CREATE TABLE [dbo].[Locations](
[LocationId] [int] IDENTITY(1,1) NOT NULL,
[Name] [nvarchar](100) NOT NULL,
[OriginalLocationId] [int] NOT NULL,
CONSTRAINT [PK_Locations] PRIMARY KEY CLUSTERED
(
[LocationId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
)
Country
CREATE TABLE [dbo].[Locations_Country](
[IsoCode] [nchar](2) NOT NULL,
[LocationId] [int] NOT NULL,
CONSTRAINT [PK_Locations_Country] PRIMARY KEY CLUSTERED
(
[LocationId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Locations_Country] WITH CHECK ADD CONSTRAINT [FK_Country_inherits_Location] FOREIGN KEY([LocationId])
REFERENCES [dbo].[Locations] ([LocationId])
GO
ALTER TABLE [dbo].[Locations_Country] CHECK CONSTRAINT [FK_Country_inherits_Location]
GO
Boundary
CREATE TABLE [dbo].[Boundaries](
[LocationId] [int] NOT NULL,
[CentrePoint] [varbinary](max) NOT NULL,
[OriginalBoundary] [varbinary](max) NULL,
[LargeReducedBoundary] [varbinary](max) NULL,
[MediumReducedBoundary] [varbinary](max) NULL,
[SmallReducedBoundary] [varbinary](max) NULL,
CONSTRAINT [PK_Boundaries] PRIMARY KEY CLUSTERED
(
[LocationId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO
SET ANSI_PADDING OFF
GO
ALTER TABLE [dbo].[Boundaries] WITH CHECK ADD CONSTRAINT [FK_LocationBoundary] FOREIGN KEY([LocationId])
REFERENCES [dbo].[Locations] ([LocationId])
GO
ALTER TABLE [dbo].[Boundaries] CHECK CONSTRAINT [FK_LocationBoundary]
GO
I don't see a need for SCOPE_IDENTITY or cursors if you approach the data in order of the parent/child relationship:
INSERT INTO LOCATION
SELECT t.name,
t.originallocationid
FROM ORIGINAL_TABLE t
GROUP BY t.name, t.originallocationid
INSERT INTO COUNTRY
SELECT DISTINCT
t.isocode,
l.locationid
FROM ORIGINAL_TABLE t
JOIN LOCATION l ON l.name = t.name
AND l.originallocationid = t.originalocationid
INSERT INTO BOUNDARY
SELECT DISTINCT
l.locationid,
t.centrepoint,
t.originalboundary,
t.largereducedboundary,
t.mediumreducedboundary,
t.smallreducedboundary
FROM ORIGINAL_TABLE t
JOIN LOCATION l ON l.name = t.name
AND l.originallocationid = t.originalocationid
After loading your Location table you could create a query that joins Location with your source single table. The join criteria would be the natural key (is that the Name column?) and it would return the new LocationId along with the Boundary data. The results would inserted into the new Boundary table.