I'm brand new to learning SQL. I have a very basic understanding of the language.
I have two tables. Storage Data is the table I ultimately want to return by [ScenarioID].
My second table, Storage Static, also has [ScenarioID], but I also need to first filter this table by two other fields [Platform] and [AccountID]. I have the following code that successfully filters this Storage Static table.
select
[ScenarioID]
from [dbo].[Storage Static]
WHERE [Platform] = 'ABC' AND [AccountID] in (select MAX([AccountID])
from [dbo].[Storage Static])
What I'm trying to do is basically embed the above code as a sub-query into my query for the original table Storage Data.
select
[ScenarioID],
[CountryID]
from [dbo].[Storage Data] t1
INNER JOIN
(
select
[ScenarioID]
from [dbo].[Storage Static]
WHERE [Platform] = 'ABC' AND [AccountID] in (select MAX([AccountID]) MaxPop
from [dbo].[Storage Static])
) t2
on t1.[ScenarioID] = t2.MaxPop
I know the MaxPop part doesn't really work but that was my attempt at assigning a name or variable to that sub-query.
Ultimately, I want to filter my original table by the list of [ScenarioID]'s that I created in the sub-query.
If I understand correctly, you just need to fix the JOIN conditions.
select sd.[ScenarioID], sd.[CountryID]
from [dbo].[Storage Data] sd join
(select [ScenarioID]
from [dbo].[Storage Static]
where [Platform] = 'ABC' and
[AccountID] in (select max([AccountID]) from [dbo].[Storage Static])
) ss
on sd.[ScenarioID] = ss.[ScenarioID]
Since you need MaxPop to be taken as a field needed for join'
instead ofinclause, I use aninner join`, so that the filed can be considered for the join.
select t1.[ScenarioID], t1.[CountryID]
from [dbo].[Storage Data] t1
INNER JOIN
(
select [ScenarioID], MaxPop
from [dbo].[Storage Static] s
Inner Join
(select MAX([AccountID]) MaxPop
from [dbo].[Storage Static]) m
on m.MaxPop = s.[AccountID]
WHERE [Platform] = 'ABC'
) t2
on t1.[ScenarioID] = t2.MaxPop
Related
I have a query that is using a temp table to insert some data then another select from to extract distinct results. That query by it self was fine but now with entity-framework it is causing all kinds of unexpected errors at the wrong time.
Is there any way I can rewrite the query not to use a temp table? When this is converted into a stored procedure and in entity framework the result set is of type int which throws an error:
Could not find an implementation of the query pattern Select not found.
Here is the query
Drop Table IF EXISTS #Temp
SELECT
a.ReceiverID,
a.AntennaID,
a.AntennaName into #Temp
FROM RFIDReceiverAntenna a
full join Station b ON (a.ReceiverID = b.ReceiverID) and (a.AntennaID = b.AntennaID)
where (a.ReceiverID is NULL or b.ReceiverID is NULL)
and (a.AntennaID IS NULL or b.antennaID is NULL)
select distinct r.ReceiverID, r.ReceiverName, r.receiverdescription
from RFIDReceiver r
inner join #Temp t on r.ReceiverID = t.ReceiverID;
No need for anything fancy, you can just replace the reference to #temp with an inner sub-query containing the query that generates #temp e.g.
select distinct r.ReceiverID, r.ReceiverName, r.receiverdescription
from RFIDReceiver r
inner join (
select
a.ReceiverID,
a.AntennaID,
a.AntennaName
from RFIDReceiverAntenna a
full join Station b ON (a.ReceiverID = b.ReceiverID) and (a.AntennaID = b.AntennaID)
where (a.ReceiverID is NULL or b.ReceiverID is NULL)
and (a.AntennaID IS NULL or b.antennaID is NULL)
) t on r.ReceiverID = t.ReceiverID;
PS: I haven't made any effort to improve the query overall like Gordon has but do consider his suggestions.
First, a full join makes no sense in the first query. You are selecting only columns from the first table, so you need that.
Second, you can use a CTE.
Third, you should be able to get rid of the SELECT DISTINCT by using an EXISTS condition.
I would suggest:
WITH ra AS (
SELECT ra.*
FROM RFIDReceiverAntenna ra
Station s
ON s.ReceiverID = ra.ReceiverID AND
s.AntennaID = ra.AntennaID)
WHERE s.ReceiverID is NULL
)
SELECT r.ReceiverID, r.ReceiverName, r.receiverdescription
FROM RFIDReceiver r
WHERE EXISTS (SELECT 1
FROM ra
WHERE r.ReceiverID = ra.ReceiverID
);
You can use CTE instead of the temp table:
WITH
CTE
AS
(
SELECT
a.ReceiverID,
a.AntennaID,
a.AntennaName
FROM
RFIDReceiverAntenna a
full join Station b
ON (a.ReceiverID = b.ReceiverID)
and (a.AntennaID = b.AntennaID)
where
(a.ReceiverID is NULL or b.ReceiverID is NULL)
and (a.AntennaID IS NULL or b.antennaID is NULL)
)
select distinct
r.ReceiverID, r.ReceiverName, r.receiverdescription
from
RFIDReceiver r
inner join CTE t on r.ReceiverID = t.ReceiverID
;
This query will return the same results as your original query with the temp table, but its performance may be quite different; not necessarily slower, it can be faster. Just something that you should be aware about.
I've been trying to understand the behavior of a query but i dont fully understand what is going on.
Take a look:
SELECT main.entity_id,main.sku,name.value AS name
FROM product_entity AS main
LEFT JOIN product_entity_varchar AS name ON main.entity_id = name.entity_id
WHERE name.attribute_id = (
SELECT attribute_id
FROM ger_attribute
WHERE attribute_code LIKE "name"
AND 'entity_type_id' = (
SELECT entity_type_id
FROM ger_entity_type
WHERE entity_type_code = 'catalog_product_info'
)
)
Can you please explain why it is using a subquery ,why the LEFT JOIN is important in these cases and the condition entity_type_code = 'catalog_product_info'?
Thanks
SELECT main.entity_id,main.sku,name.value AS name
FROM product_entity AS main
LEFT JOIN product_entity_varchar AS name ON main.entity_id = name.entity_id
...
The query starts by pulling out table product_entity. The LEFT JOIN allows the query to access the record(s) in table product_entity_varchar whose entity_id is equal to the value of the column that has the same name in product_entity.
In the resultset, the value of column value from table product_entity_varchar is displayed, under alias name.
The keyword LEFT makes the relation optional ; it there is no matching record in product_entity_varchar, the name will simply appear as NULL in the output. If it were an [INNER] JOIN, then the relation would be mandatory : unmatched records would be filtered out, and would not appear in the output.
OK. Let's clarify what is LEFT OUTER JOIN in SQL.
LEFT JOIN queries could be understood as just syntax abbreviation of UNION ALL of INNER JOIN-ed and NOT EXIST-ed queries.
Let's decompose LEFT JOIN-ed query:
SELECT main.entity_id,main.sku,name.value AS name
FROM
product_entity AS main
LEFT JOIN product_entity_varchar AS name ON main.entity_id = name.entity_id
WHERE
name.attribute_id = (
SELECT attribute_id
FROM ger_attribute
WHERE attribute_code LIKE "name"
AND 'entity_type_id' = (
SELECT entity_type_id
FROM ger_entity_type
WHERE entity_type_code = 'catalog_product_info'
)
)
Is equivalent to:
SELECT main.entity_id,main.sku,name.value AS name
FROM
product_entity AS main
JOIN product_entity_varchar AS name
ON main.entity_id = name.entity_id
WHERE
name.attribute_id = (
SELECT attribute_id
FROM ger_attribute
WHERE attribute_code LIKE "name"
AND 'entity_type_id' = (
SELECT entity_type_id
FROM ger_entity_type
WHERE entity_type_code = 'catalog_product_info'
)
)
UNION ALL
SELECT main.entity_id,main.sku, NULL AS name -- <-- Attention!
FROM
product_entity AS main
NOT EXISTS(
SELECT * FROM product_entity_varchar AS name
WHERE
main.entity_id = name.entity_id
AND name.attribute_id = (
SELECT attribute_id
FROM ger_attribute
WHERE attribute_code LIKE "name"
AND 'entity_type_id' = (
SELECT entity_type_id
FROM ger_entity_type
WHERE entity_type_code = 'catalog_product_info'
)
)
)
I hope this will help to understand query, although it's impossible without data to answer "why it is using a subquery" etc.
My weakest area of SQL are self JOINS, currently struggling with an issue.
I need to find the latest entry in a table, I'm using a WHERE DATEFIELD IN (SELECT MAX(DATEFIELD) FROM TABLE) to do this. I then need to establish if 3 columns from that already exist in the same TABLE.
My latest attempt looks like this -
SELECT * FROM PART_TABLE
WHERE NOT EXISTS
(
SELECT
t1.DATEFIELD
t1.CODE1
t1.CODE2
t1.CODE3
FROM PART_TABLE t1
INNER JOIN PART_TABLE t2 ON t1.UNIQUE = t2.UNQIUE
)
WHERE t1.DATEFIELD IN
(
SELECT MAX(DATEFIELD)
FROM PARTTABLE
)
)
I think part of the issue is that I can't exclude the unique row from t1 when checking in t2 using this method.
Using MSSQL 2014.
The following query will return the latest record from your table and a bit flag whether a duplicate tuple {Code1, Code2, Code3} exists in it under a different identifier:
select top (1) p.*,
case when exists (
select 0 from dbo.Part_Table t where t.Unique != p.Unique
and t.Code1 = p.Code1 and t.Code2 = p.Code2 and t.Code3 = p.Code3
) then 1
else 0 end as [IsDuplicateExists]
from dbo.Part_Table p
order by p.DateField desc;
You can use this example as a template to address your specific needs, which unfortunately aren't immediately apparent from your explanation.
I have a working sql select, which looks like this
[Edited: Im sorry i did one mistake in the question, i edited alias of Table1 but im trying the answers]
SELECT
m.Column1
,t2.Column2
,COALESCE
(
(
SELECT TOP 1 Vat
FROM LinkedDBServer.DatabaseName.dbo.TableName t3
WHERE
m.MaterialNumber = t3.MaterialNumber COLLATE Czech_CI_AS
and t3.Currency = …
and ...
ORDER BY [Date] DESC
), m.Vat
) as Vat
FROM Table1 m
JOIN Table2 t2 on (m.Column1 = t2.Column1)
It works but the problem is that it takes too long and LinkedServer cut my connection because it takes more than 10 minutes. The purpose of the query is to get newer data from a different database if it exists (i get newest data by top and ordering it by date and precondition is that every data in that database is newer than in mine, thats why im using COALESCE).
But my though is if I was able to rewrite it to JOIN it could be faster. But another problem could be I dont have an primary key (and cant change that).
How can I speed that query up ? (Im using SQL Server 2008 R2)
Thank you
Here i attached Estimated Query Plan: (Its readable in browser ZOOM :) Estimation is for 2 Coalesce columns.
Try rewriting query using outer apply
SELECT
t1.Column1
,t2.Column2
,COALESCE(ou.vat, m.Vat) as Vat
FROM Table1 t1
JOIN Table2 m on (m.Column1 = t1.Column1)
outer apply
(
SELECT TOP 1 Vat
FROM LinkedDBServer.DatabaseName.dbo.TableName t3
WHERE
m.MaterialNumber = t3.MaterialNumber COLLATE Czech_CI_AS
and t3.Currency = …
and ...
ORDER BY [Date] DESC
) ou
Another option:
; WITH vat AS (
SELECT MaterialNumber COLLATE Czech_CI_AS As MaterialNumber
, Vat
, Row_Number() OVER (PARTITION BY MaterialNumber ORDER BY "Date" DESC) As sequence
FROM LinkedDBServer.DatabaseName.dbo.TableName
WHERE Currency = ...
AND ...
)
SELECT t1.Column1
, m.Column2
, Coalesce(vat.Vat, m.Vat) As Vat
FROM Table1 As t1
INNER
JOIN Table2 As m
ON m.Column1 = t1.Column1
LEFT
JOIN vat
ON vat.MaterialNumber = m.MaterialNumber
AND vat.sequence = 1
;
Is it not possible to use the "as [item] and then use the item variable in the query.
For example:
select c.category as [category],c.orderby as [CatOrder], m.masterno, m.master
,-- select OUT (select count(*) from rentalitem ri with (nolock),
rentalitemstatus ris with (nolock),
rentalstatus rs with (nolock)
where ri.rentalitemid = ris.rentalitemid
and ris.rentalstatusid = rs.rentalstatusid
and ri.masterid = m.masterid
and rs.statustype in ('OUT', 'INTRANSIT', 'ONTRUCK')) as [qtyout]
,-- select OWNED owned=
(select top 1 mwq.qty
from masterwhqty mwq
where mwq.masterid = m.masterid)
, -([owned]-[qtyout]) as [Variance]
from master m
inner join category c on c.categoryid=m.categoryid and c.categoryid=#category
inner join inventorydepartment d on c.inventorydepartment=#department
I cannot seem to use qtyout or owned when calculating variance. How can I do that?
You can also use a table variable and then reference that table variable like you are trying to do above....here's an example from MSDN
USE AdventureWorks2012;
GO
DECLARE #MyTableVar table(
EmpID int NOT NULL,
OldVacationHours int,
NewVacationHours int,
ModifiedDate datetime);
UPDATE TOP (10) HumanResources.Employee
SET VacationHours = VacationHours * 1.25,
ModifiedDate = GETDATE()
OUTPUT inserted.BusinessEntityID,
deleted.VacationHours,
inserted.VacationHours,
inserted.ModifiedDate
INTO #MyTableVar;
--Display the result set of the table variable.
SELECT EmpID, OldVacationHours, NewVacationHours, ModifiedDate
FROM #MyTableVar;
GO
--Display the result set of the table.
SELECT TOP (10) BusinessEntityID, VacationHours, ModifiedDate
FROM HumanResources.Employee;
GO
need to move your calculated fields into a subquery, and then use them by their alias in the outer query.
select subquery.*, -([owned]-[qtyout]) as [Variance]
from
(
select c.category as [category],c.orderby as [CatOrder], m.masterno, m.master
,-- select OUT (select count(*) from rentalitem ri with (nolock),
rentalitemstatus ris with (nolock),
rentalstatus rs with (nolock)
where ri.rentalitemid = ris.rentalitemid
and ris.rentalstatusid = rs.rentalstatusid
and ri.masterid = m.masterid
and rs.statustype in ('OUT', 'INTRANSIT', 'ONTRUCK')) as [qtyout]
,-- select OWNED owned=
(select top 1 mwq.qty
from masterwhqty mwq
where mwq.masterid = m.masterid) as [owned]
from master m
inner join category c on c.categoryid=m.categoryid and c.categoryid=#category
inner join inventorydepartment d on c.inventorydepartment=#department
) as subquery
YOu need to use a subquery:
select t.*,
([owned]-[qtyout]) as [Variance]
from (<something like your query here
) t
You query, even without the comments, doesn't quite make sense (select OUT (select . . . for isntance). But, the answer to your question is to define the base variables in a subquery or CTE and then subsequently use them.
And, you are calling the difference "variance". Just so you know, you are redefining the statistical meaning of the term (http://en.wikipedia.org/wiki/Variance), which is based on the squares of the differences.