Learning SQL now, not particular big of temp table, since you have to drop each time you run your query. Basically this query below pulls info from patientinfo table and put into a temp table, then can be used to possibly join with another table Anyway to modify this query, so I don't need to use temp tables? Like I mean anyway to pull info from the table without a temp table, like that part where I commented out (into)
SELECT PatientCode [Code]
, PatientID [Pltid]
, CASE WHEN PatientStatus = 'R' THEN 'lefthospital'
WHEN PatientStatus = 'I' THEN 'StillIn'
ELSE 'unknown' END [CDStatus]
INTO #PatientInfoPull
FROM PatientInfo
SELECT PatientInfo.*
FROM #initCDPull
this query below pulls info from patientinfo table and put into a temp table, then can be used to possibly join with another table
Okay, you're doing something like this:
SELECT <fields>
INTO #SomeTemp
FROM SomeReal
WHERE SomeColumn = 'SomeValue'
SELECT *
FROM SomeOtherReal r
JOIN #SomeTemp t ON r.SomeOtherColumn = t.SomeOtherColumn
In that case, you can use a sub-query (formally: "Derived Table") like this:
SELECT *
FROM SomeOtherReal r
JOIN (
SELECT <fields>
FROM SomeReal
WHERE SomeColumn = 'SomeValue'
) t ON r.SomeOtherColumn = t.SomeOtherColumn
or a Common Table Expression (CTE) like this:
WITH t AS (
SELECT <fields>
FROM SomeReal
WHERE SomeColumn = 'SomeValue'
)
SELECT *
FROM SomeOtherReal r
JOIN t ON r.SomeOtherColumn = t.SomeOtherColumn
Even more than that, you can usually combine the steps like this:
SELECT t.<fields>, r.<fields>
FROM SomeOtherReal r
JOIN SomeReal t ON t.SomeOtherColumn = r.SomeOtherColumn
WHERE t.SomeColumn = 'SomeValue'
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 am trying to make a query that works with a temp table, work without that temp table
I tried doing a join in the subquery without the temp table but I don't get the same results as the query with the temp table.
This is the query with the temp table that works as I want:
create table #results(
RowId id_t,
LastUpdatedAt date_T
)
insert into #results
select H.RowId, H.LastUpdatedAt from MemberCarrierMap M Join MemberCarrierMapHistory H on M.RowId = H.RowId
update MemberCarrierMap
set CreatedAt = (select MIN(LastUpdatedAt) from #results r where r.rowId = MemberCarrierMap.rowId)
Where CreatedAt is null;
and here is the query I tried without the temp table that doesn't work like the above:
update MemberCarrierMap
set CreatedAt = (select MIN(MH.LastUpdatedAt) from MemberCarrierMapHistory MH join MemberCarrierMap M on MH.RowId = M.RowId where MH.RowId = M.RowId )
Where CreatedAt is null;
I was expecting the 2nd query to work as the first but It is not. Any suggestions on how to achieve what the first query does without the temp table?
This should work:
update M
set M.CreatedAt = (select MIN(MH.LastUpdatedAt) from MemberCarrierMapHistory MH WHERE MH.RowId = M.RowId)
FROM MemberCarrierMap M
Where M.CreatedAt is null;
Your question is more or less a duplicate of this answer. There, you will find multiple solutions. But the ones that implement correlated subqueires are less performant than the one that simply uses an uncorrelated aggregation subquery inside a join.
Applying it to your situation, you will have this:
update m
set m.createdDate = hAgg.maxVal
from memberCarrierMap m
join (
select rowId, max(lastUpdatedAt) as maxVal
from memberCarrierMapHistory
group by rowId
) as hAgg
on m.rowId = hAgg.rowId
where m.createdAt is null;
Basically, it's more performant because it is more expensive to run aggregations and filterings on a row-by-row basis (which is what happens in a correlated subquery) than to just get the aggregations out of the way all at once (joins tend to happen early in processing) and perform the match afterwards.
So I have a table, lets call it MAIN table, it has the following example columns
Name,
Code_1,
Code_2,
Code_3,
Code_4,
Code_5
(in my real example there's 25 Code columns)
I have a set of 300 codes that I inserted into a temporary table, what would be the best way to get the rows from the MAIN table where it matches a code from the temporary table?
Here's what I have so far that works, but it seems extremely inefficient
SELECT * FROM MAIN WHERE (CODE_1 IN (SELECT CODE FROM TMP_TABLE)
OR CODE_2 IN(SELECT CODE FROM TMP_TABLE)
OR CODE_3 IN (SELECT CODE FROM TMP_TABLE)
OR CODE_4 IN (SELECT CODE FROM TMP_TABLE)
OR CODE_5 IN (SELECT CODE FROM TMP_TABLE))
One approach would be to use a correlated subquery:
SELECT *
FROM MAIN m
WHERE EXISTS (
SELECT *
FROM TMP_TABLE t
WHERE t.CODE = m.CODE_1 OR t.CODE = m.CODE_2 OR ...
)
A join would be faster
SELECT * FROM MAIN
inner join TMP_TABLE
on main.code_1 = tmp_table.code
or main.code_2 = tmp_table.code
or main.code_3 = tmp_table.code
or main.code_4 = tmp_table.code
or main.code_5 = tmp_table.code
But as mentioned in the comment, the join could potentially increase the number of rows if in the main table multiple code_## match the join criteria in the tmp_table
What would the syntax be to convert this MS Access query to run in SQL Server as it doesn't have a DistinctRow keyword
UPDATE DISTINCTROW [MyTable]
INNER JOIN [AnotherTable] ON ([MyTable].J5BINB = [AnotherTable].GKBINB)
AND ([MyTable].J5BHNB = [AnotherTable].GKBHNB)
AND ([MyTable].J5BDCD = [AnotherTable].GKBDCD)
SET [AnotherTable].TessereCorso = [MyTable].[J5F7NR];
DISTINCTROW [MyTable] removes duplicate MyTable entries from the results. Example:
select distinctrow items
items.item_number, items.name
from items
join orders on orders.item_id = items.id;
In spite of the join getting you the same item_number and name multiple times when there is more than one order for it, DISTINCTROW reduces this to one row per item. So the whole join is merely for assuring that you only select items for which exist at least one order. You don't find DISTINCTROW in any other DBMS as far as I know. Probably because it is not needed. When checking for existence, we use EXISTS of course (or IN for that matter).
You are joining MyTable and AnotherTable and expect for some reason to get the same MyTable record multifold for one AnotherTable record, so you use DISTINCTROW to only get it once. Your query would (hopefully) fail if you got two different MyTable records for one AnotherTable record.
What the update does is:
update anothertable
set tesserecorso = (select top 1 j5f7nr from mytable where mytable.j5binb = anothertable.gkbinb and ...)
where exists (select * from mytable where mytable.j5binb = anothertable.gkbinb and ...)
But this uses about the same subquery twice. So we'd want to update from a query instead.
The easiest way to get one result record per <some columns> in a standard SQL query is to aggregate data:
select *
from anothertable a
join
(
select j5binb, j5bhnb, j5bdcd, max(j5f7nr) as j5f7nr
from mytable
group by j5binb, j5bhnb, j5bdcd
) m on m.j5binb = a.gkbinb and m.j5bhnb = a.gkbhnb and m.j5bdcd = a.gkbdcd;
How to write an updateble query is different from one DBMS to another. Here is the final update statement for SQL-Server:
update a
set a.tesserecorso = m.j5f7nr
from anothertable a
join
(
select j5binb, j5bhnb, j5bdcd, max(j5f7nr) as j5f7nr
from mytable
group by j5binb, j5bhnb, j5bdcd
) m on m.j5binb = a.gkbinb and m.j5bhnb = a.gkbhnb and m.j5bdcd = a.gkbdcd;
The DISTINCTROW predicate in MS Access SQL removes duplicates across all fields of a table in join statements and not just the selected fields of query (which DISTINCT in practically all SQL dialects do). So consider selecting all fields in a derived table with DISTINCT predicate:
UPDATE [AnotherTable]
SET [AnotherTable].TessereCorso = main.[J5F7NR]
FROM
(SELECT DISTINCT m.* FROM [MyTable] m) As main
INNER JOIN [AnotherTable]
ON (main.J5BINB = [AnotherTable].GKBINB)
AND (main.J5BHNB = [AnotherTable].GKBHNB)
AND (main.J5BDCD = [AnotherTable].GKBDCD)
Another variant of the query.. (Too lazy to get the original tables).
But like the query above updates 35 rows =, so does this one
UPDATE [Albi-Anagrafe-Associati]
SET
[Albi-Anagrafe-Associati].CRegDitte = [055- Registri ditte].[CRegDitte],
[Albi-Anagrafe-Associati].NIscrTribunale = [055- Registri ditte].[NIscrTribunale],
[Albi-Anagrafe-Associati].NRegImprese = [055- Registri ditte].[NRegImprese]
FROM [055- Registri ditte]
WHERE EXISTS(
SELECT *
FROM [055- Registri ditte]-- [Albi-Anagrafe-Associati]
WHERE ([055- Registri ditte].GIBINB = [Albi-Anagrafe-Associati].GKBINB)
AND ([055- Registri ditte].GIBHNB = [Albi-Anagrafe-Associati].GKBHNB)
AND ([055- Registri ditte].GIBDCD = [Albi-Anagrafe-Associati].GKBDCD))
Update [AnotherTable]
Set [AnotherTable].TessereCorso = MyTable.[J5F7NR]
From [AnotherTable]
Inner Join
(
Select Distinct [J5BINB],[5BHNB],[J5BDCD]
,(Select Top 1 [J5F7NR] From MyTable) as [J5F7NR]
,[J5BHNB]
From MyTable
)as MyTable
On (MyTable.J5BINB = [AnotherTable].GKBINB)
AND (MyTable.J5BHNB = [AnotherTable].GKBHNB)
AND (MyTable.J5BDCD = [AnotherTable].GKBDCD)
Suppose I have an sql query like the following (I realize this query could be written better, just bear with me):
SELECT aT.NAME
FROM anothertable aT,
( SELECT ts.slot_id,
tgm.trans_id,
tagm.agent_id
FROM slots ts,
transactions tgm,
agents tagm
WHERE ts.slot_id = (12345, 678910)
and ts.slot_id = tagm.slot_id
AND ts.slot_id = tgm.slot_id) INNER
WHERE INNER.trans_id = aT.trans_id
AND INNER.agent_id = aT.trans_id
Now suppose that I need to break up this query into two parts...in the first I'll execute the inner query, do some processing on the results in code, and then pass back a reduced set to the outer part of the query. The question is, is there an easy way to emulate an inner table in sql?
For instance, if the results of the inner query returned 5 rows but my program deems to only need two of those rows, how can I write sql that will do what I am trying to do below? Is there a way, in sql, to declare a table for in memory in query use?
SELECT
at.Name
FROM
anotherTable aT,
(SLOT_ID, TRANS_ID, AGENT_ID
-------------------------
230743, 3270893, 2307203
078490, 230897, 237021) inner
WHERE
inner.trans_id = at.trans_id
AND INNER.agent_id = aT.trans_id
Just use a subquery:
SELECT at.Name
FROM anotherTable aT JOIN
(select 230743 as SLOT_ID, 3270893 as TRANS_ID, 2307203 as AGENT_ID from dual
select 078490, 230897, 237021 from dual
) i
on i.trans_id = at.trans_id AND i.agent_id = aT.trans_id;
Most systems will let you define a TEMP TABLE or TABLE VARIABLE: https://www.simple-talk.com/sql/t-sql-programming/temporary-tables-in-sql-server/
CREATE TABLE #temp (
SLOT_ID INT,
TRANS_ID INT,
AGENT_ID INT
);
INSERT INTO #temp(SLOT_ID, TRANS_ID, AGENT_ID)
(--inner query goes here)
--do your main query, then:
DROP TABLE #temp
IN MS SQL Server (not sure about other systems), you could possibly use a Common Table Expression (CTE): https://technet.microsoft.com/en-us/library/ms190766%28v=sql.105%29.aspx
WITH inner AS (
--inner query goes here
)
--main select goes here
Personally, since I generally work with MSSQL Server, I use CTE's quite a bit, as they can be created "on the fly", and can be a big help in organizing more complex queries.
The subquery method worked. Since this is Oracle, the syntax turned out to be:
SELECT aT.Name
FROM anotherTable aT,
(select 1907945 as SLOT_ID, 2732985 as TRANS_ID, 40157 as AGENT_ID FROM DUAL
union
select 1907945, 2732985, 40187 FROM DUAL
) inner
WHERE
inner.trans_id = aT.trans_id AND INNER.agent_id = aT.trans_id;