SQL Server Query optimisation question - sql

I have the following queries, and I would love to find a better way to do this as it doesn't seem right the way I am doing it...
EDIT
Sorry I did not specify that I only want to return adverts that actually match all amenities!
SELECT TOP 50 Advert.Id
FROM Advert
WHERE Id in(SELECT Advert_id FROM AdvertsToAmenities WHERE Amenity_id = 1 AND Advert_Id = Id)
AND Id in(SELECT Advert_id FROM AdvertsToAmenities WHERE Amenity_id = 3 AND Advert_Id = Id)
AND Id in(SELECT Advert_id FROM AdvertsToAmenities WHERE Amenity_id = 5 AND Advert_Id = Id)
-- OR --
SELECT TOP 50 Advert.Id
FROM Advert
JOIN AdvertsToAmenities a on Advert.Id = a.Advert_id
JOIN AdvertsToAmenities b on Advert.Id = b.Advert_id
JOIN AdvertsToAmenities c on Advert.Id = c.Advert_id
WHERE a.Amenity_id = 1
AND b.Amenity_id = 3
AND c.Amenity_id = 5
I would love to find out how to optimize these queries!

Your queries look fine to me. Another alternative would be to use something like this:
SELECT TOP 50 Advert.Id
FROM Advert JOIN AdvertsToAmenities a ON Advert.Id = a.Advert_id
WHERE a.Amenity_id = 1
OR a.Amenity_id = 3
OR a.Amenity_id = 5
GROUP BY Advert.Id
HAVING COUNT(DISTINCT a.Amenity_id) = 3
If the (Advert_Id, Amenity_id) pairs are unique, you can drop the DISTINCT.

How about the following restructure of your query which allows you to simply create a comma seperated list of specific amenity IDs?
SELECT TOP 50
a.[ID]
FROM [Advert] a
INNER JOIN
(
SELECT ata.[Advert_ID]
FROM [AdvertsToAmenities] ata
WHERE ata.[Amenity_ID]
IN (1, 3, 4, 5) -- Your list of amenity IDs
) as ata
ON a.[ID] = ata.[Advert_ID]
This uses a dynamic table statement to prefilter only those applicable amenities before joining back against the list of adverts. Note, Sql Server will heavily optimise the sub query before execution. This should mean that you'll get the benefit of a more maintainable statement with all the optimisations that Sql Server provides.

* Try this simple *
SELECT TOP 50 a.Id
FROM Advert a, AdvertsToAmenities b
WHERE a.Amenity_id in ('1','3','5')
and a.Id = b.Amenity_id

Related

How to select data from table with big rows where column like column1%column2

I have a table Product with 240 000 rows.
I want to select from this table data where idproduct = idproductcomponent
Output makes a table with 3 columns A12345678 35655455952625 9638520963258960, so in different column.
Always idproductcomponent of idproducttype 1 is 0, and idproductcomponent of idproducttype 2,3 are the same of idproduct of idproducttype 1.
Pelase, can you share with me any idea for this select ?
Assuming your database is SQL Server (you don't say which one it is) the query could look like:
select
a.name,
b.name,
c.name
from t a
left join t b on b.idproductcomponent = a.idproduct and b.idproducttype = 2
left join t c on c.idproductcomponent = a.idproduct and c.idproducttype = 3
where a.idproducttype = 1
and a.idproduct = 11163 -- parameter you are searching for
To increase the performance of this query you can add the index:
create index ix1 on t (idproductcomponent);

SELECT NOT IN with multiple columns in subquery

Regarding the statement below, sltrxid can exist as both ardoccrid and ardocdbid. I'm wanting to know how to include both in the NOT IN subquery.
SELECT *
FROM glsltransaction A
INNER JOIN cocustomer B ON A.acctid = B.customerid
WHERE sltrxstate = 4
AND araccttype = 1
AND sltrxid NOT IN(
SELECT ardoccrid,ardocdbid
FROM arapplyitem)
I would recommend not exists:
SELECT *
FROM glsltransaction t
INNER JOIN cocustomer c ON c.customerid = t.acctid
WHERE
??.sltrxstate = 4
AND ??.araccttype = 1
AND NOT EXISTS (
SELECT 1
FROM arapplyitem a
WHERE ??.sltrxid IN (a.ardoccrid, a.ardocdbid)
)
Note that I changed the table aliases to things that are more meaningful. I would strongly recommend prefixing the column names with the table they belong to, so the query is unambiguous - in absence of any indication, I represented this as ?? in the query.
IN sometimes optimize poorly. There are situations where two subqueries are more efficient:
SELECT *
FROM glsltransaction t
INNER JOIN cocustomer c ON c.customerid = t.acctid
WHERE
??.sltrxstate = 4
AND ??.araccttype = 1
AND NOT EXISTS (
SELECT 1
FROM arapplyitem a
WHERE ??.sltrxid = a.ardoccrid
)
AND NOT EXISTS (
SELECT 1
FROM arapplyitem a
WHERE ??.sltrxid = a.ardocdbid
)

How can I join on multiple columns within the same table that contain the same type of info?

I am currently joining two tables based on Claim_Number and Customer_Number.
SELECT
A.*,
B.*,
FROM Company.dbo.Company_Master AS A
LEFT JOIN Company.dbp.Compound_Info AS B ON A.Claim_Number = B.Claim_Number AND A.Customer_Number = B.Customer_Number
WHERE A.Filled_YearMonth = '201312' AND A.Compound_Ind = 'Y'
This returns exactly the data I'm looking for. The problem is that I now need to join to another table to get information based on a Product_ID. This would be easy if there was only one Product_ID in the Compound_Info table for each record. However, there are 10. So basically I need to SELECT 10 additional columns for Product_Name based on each of those Product_ID's that are being selected already. How can do that? This is what I was thinking in my head, but is not working right.
SELECT
A.*,
B.*,
PD_Info_1.Product_Name,
PD_Info_2.Product_Name,
....etc {Up to 10 Product Names}
FROM Company.dbo.Company_Master AS A
LEFT JOIN Company.dbo.Compound_Info AS B ON A.Claim_Number = B.Claim_Number AND A.Customer_Number = B.Customer_Number
LEFT JOIN Company.dbo.Product_Info AS PD_Info_1 ON B.Product_ID_1 = PD_Info_1.Product_ID
LEFT JOIN Company.dbo.Product_Info AS PD_Info_2 ON B.Product_ID_2 = PD_Info_2.Product_ID
.... {Up to 10 LEFT JOIN's}
WHERE A.Filled_YearMonth = '201312' AND A.Compound_Ind = 'Y'
This query not only doesn't return the correct results, it also takes forever to run. My actual SQL is a lot longer and I've changed table names, etc but I hope that you can get the idea. If it matters, I will be creating a view based on this query.
Please advise on how to select multiple columns from the same table correctly and efficiently. Thanks!
I found put my extra stuff into CTE and add ROW_NUMBER to insure that I get only 1 row that I care about. it would look something like this. I only did for first 2 product info.
WITH PD_Info
AS ( SELECT Product_ID
,Product_Name
,Effective_Date
,ROW_NUMBER() OVER ( PARTITION BY Product_ID, Product_Name ORDER BY Effective_Date DESC ) AS RowNum
FROM Company.dbo.Product_Info)
SELECT A.*
,B.*
,PD_Info_1.Product_Name
,PD_Info_2.Product_Name
FROM Company.dbo.Company_Master AS A
LEFT JOIN Company.dbo.Compound_Info AS B
ON A.Claim_Number = B.Claim_Number
AND A.Customer_Number = B.Customer_Number
LEFT JOIN PD_Info AS PD_Info_1
ON B.Product_ID_1 = PD_Info_1.Product_ID
AND B.Fill_Date >= PD_Info_1.Effective_Date
AND PD_Info_2.RowNum = 1
LEFT JOIN PD_Info AS PD_Info_2
ON B.Product_ID_2 = PD_Info_2.Product_ID
AND B.Fill_Date >= PD_Info_2.Effective_Date
AND PD_Info_2.RowNum = 1

Tricky SQLite query, could use some assistance

I have a rather confusing SQLite query that I can't seem to quite wrap my brain around.
I have the following four tables:
Table "S"
sID (string/guid) | sNum (integer)
-----------------------------------
aaa-aaa 1
bbb-bbb 2
ccc-ccc 3
ddd-ddd 4
eee-eee 5
fff-fff 6
ggg-ggg 7
Table "T"
tID (string/guid) | ... other stuff
-----------------------------------
000
www
xxx
yyy
zzz
Table "S2TMap"
sID | tID
-------------------
aaa-aaa 000
bbb-bbb 000
ccc-ccc xxx
ddd-ddd yyy
eee-eee www
fff-fff 000
ggg-ggg 000
Table "temp"
oldID (string/guid) | newID (string/guid)
------------------------------------------
dont care fff-fff
dont care ggg-ggg
dont care zzz
What I need is to be able to get the MAX() sNum that exists in a specified "t" if the sID doesn't exist in the temp.NewID table.
For example, given the T '000', '000' has S 'aaa-aaa', 'bbb-bbb', 'fff-fff', and 'ggg-ggg' mapped to it. However, both 'fff-fff' and 'ggg-ggg' exist in the TEMP table, which means I need to only look at 'aaa-aaa' and 'bbb-bbb'. Thus, the statement would return "2".
How would I go about doing this?
I was thinking something along the lines of the following for selecting s that don't exist in the "temp" table, but I'm not sure how to get the max of the seat and only do it based on a specific 't'
SELECT s.sID, s.sNum FROM s WHERE NOT EXISTS ( SELECT newID from temp where tmp.newID = s.sID)
Thanks!
Give this a try:
select max(s.sNum) result from s2tmap st
join s on st.sId = s.sId
where st.tId = '000' and not exists (
select * from temp
where temp.newId = st.sId)
Here is the fiddle to play with.
Another option, probably less efficient would be:
select max(s.sNum) result from s2tmap st
join s on st.sId = s.sId
where st.tId = '000' and st.sId not in (
select newId from temp)
The following query should give you a list of Ts and their max sNums (as long as all exist in S and S2TMap):
SELECT t.tID, MAX(sNum)
FROM S s
JOIN S2TMap map on s.sID=map.sID
JOIN T t on map.tId=t.tID
LEFT JOIN temp tmp on s.sID=tmp.newID
WHERE tmp.newID IS NULL
You were close, you just had to join on S2TMap and then to T in order to restrict the result set to a given T.
SELECT MAX(s.sNum)
FROM s
INNER JOIN S2TMap m on m.sID = s.sID
INNER JOIN t on t.tID = m.tID
WHERE t.tID = '000'
AND NOT EXISTS (
SELECT newID FROM temp WHERE temp.newID = s.sID
)

Using (IN operator) OR condition in Where clause as AND condition

Please look at following image, I have explained my requirements in the image.
alt text http://img30.imageshack.us/img30/5668/shippment.png
I can't use here WHERE UsageTypeid IN(1,2,3,4) because this will behave as an OR condition and fetch all records.
I just want those records, of first table, which are attached with all 4 ShipmentToID .
All others which are attached with 3 or less ShipmentToIDs are not needed in result set.
Thanks.
if (EntityId, UsageTypeId) is unique:
select s.PrimaryKeyField, s.ShipmentId from shipment s, item a
where s.PrimaryKeyField = a.EntityId and a.UsageTypeId in (1,2,3,4)
group by s.PrimaryKeyField, s.ShipmentId having count(*) = 4
otherwise, 4-way join for the 4 fields,
select distinct s.* from shipment s, item a, item b, item c, item d where
s.PrimaryKeyField = a.EntityId = b.EntityId = c.EntityId = d.EntityId and
a.UsageTypeId = 1 and b.UsageTypeId = 2 and c.UsageTypeId = 3 and
d.UsageTypeId = 4
you'll want appropriate index on (EntityId, UsageTypeId) so it doesn't hang...
If there will never be duplicates of the UsageTypeId-EntityId combo in the 2nd table, so you'll never see:
EntityUsageTypeId | EntityId | UsageTypeId
22685 | 4477 | 1
22687 | 4477 | 1
You can count matching EntityIds in that table.
WHERE (count(*) in <tablename> WHERE EntityId = 4477) = 4
DECLARE #numShippingMethods int;
SELECT #numShippingMethods = COUNT(*)
FROM shippedToTable;
SELECT tbl1.shipmentID, COUNT(UsageTypeId) as Usages
FROM tbl2 JOIN tbl1 ON tbl2.EntityId = tbl1.EntityId
GROUP BY tbl1.EntityID
HAVING COUNT(UsageTypeId) = #numShippingMethods
This way is preferred to the multiple join against same table method, as you can simply modify the IN clause and the COUNT without needing to add or subtract more tables to the query when your list of IDs changes:
select EntityId, ShipmentId
from (
select EntityId
from (
select EntityId
from EntityUsage eu
where UsageTypeId in (1,2,3,4)
group by EntityId, UsageTypeId
) b
group by EntityId
having count(*) = 4
) a
inner join Shipment s on a.EntityId = s.EntityId