Does anyone know a way to simplify this WHERE expression?
WHERE (
(#UserSpecialtyID in
(
SELECT CharacteristicSpecialties_Id
FROM ModalityVariantSpecialty
WHERE ModalityVariants_Id = ModalityVariants.Id
)
)
OR
NOT EXISTS
(
SELECT CharacteristicSpecialties_Id
FROM ModalityVariantSpecialty
WHERE ModalityVariants_Id = ModalityVariants.Id
)
)
Something like this should probably work but Im not exactly clear on the relationships for your tables. I could probably give a better example if you could explain the relationships.
SELECT
*
FROM MadalityVariants mv
LEFT JOIN ModalityVariantSpecialty mvs on mvs.ModalityVariants_ID = mv.ID
WHERE
#UserSpecialtyID = mvs.CharacteristicSpecialties_ID
OR
mvs.CharacteristicSpecialties_ID is null
WHERE (
#UserSpecialtyID in
(
SELECT COALESCE(CharacteristicSpecialties_Id, A.A)
FROM (SELECT #UserSpecialtyID A) A LEFT JOIN ModalityVariantSpecialty
ON ModalityVariants_Id = ModalityVariants.Id
)
)
this works well if CharacteristicSpecialties_Id is a NON NULLABLE field.
I am assuming that this is a WHERE clause of a SELECT on the table ModalityVariants
Would this work (The SQL is not tested)?
SELECT *
FROM ModalityVariants
LEFT OUTER JOIN ModalityVariantSpeciality
ON ModalityVariants.Id = ModalityVariants_ID
WHERE CharacteristicSpecialities_Id = #UserSpecialityID or
CharacteristicSpecialities_Id is NULL
Here's my attempt:
WHERE #UserSpecialtyID = COALESCE
(
SELECT TOP 1 CharacteristicSpecialties_Id
FROM ModalityVariantSpecialty
WHERE ModalityVariants_Id = ModalityVariants.Id
ORDER BY
CASE WHEN CharacteristicSpecialties_Id = UserSpecialtyID THEN 1
ELSE 2 END ASC
), #UserSpecialtyID)
If both ModalityVariants_Id and UserSpecialtyID match, the subquery returns CharacteristicSpecialties_Id, and the where succeeds
If only ModalityVariants_Id matches, the subquery returns a different ID, and the where fails
If neither matches, the subquery returns NULL, the COALESCE returns #UserSpecialtyID, and the where succeeds
Probably clearest is a variety of John Hartsock's answer, with a subquery to ensure the left join doesn't add any rows.
select *
from ModalityVariants mv
left join
(
select distinct ModalityVariants_ID
, CharacteristicSpecialties_ID
from ModalityVariantSpecialty
) as mvs
on mvs.ModalityVariants_ID = mv.ID
where #UserSpecialtyID = mvs.CharacteristicSpecialties_ID
OR
mvs.CharacteristicSpecialties_ID is null
I'll vote for John's answer :)
Related
My query should stop inserting values, as the not exists statement is satisfied (I have checked both tables) and matching incidents exist in both tables, any ideas why values are still being returned?
Here is the code:
INSERT INTO
odwh_system.ead_incident_credit_control_s
(
incident
)
SELECT DISTINCT
tp.incident
FROM
odwh_data.ead_incident_status_audit_s ei
INNER JOIN odwh_data.ead_incident_s tp ON ei.incident=tp.incident
WHERE
ei.status = 6
OR
ei.status = 7
AND NOT EXISTS
(
SELECT
true
FROM
odwh_system.ead_incident_credit_control_s ead
WHERE
ead.incident = tp.incident
)
AND EXISTS
(
SELECT
true
FROM
odwh_work.ead_incident_tp_s tp
WHERE
tp.incident = ei.incident
);
dont reuse table aliases
use sane aliases
avoid AND/OR conflicts; prefer IN()
INSERT INTO odwh_system.ead_incident_credit_control_s (incident)
SELECT -- DISTINCT
tp.incident
FROM odwh_data.ead_incident_s dtp
WHERE NOT EXISTS (
SELECT *
FROM odwh_system.ead_incident_credit_control_s sic
WHERE sic.incident = dtp.incident
)
AND EXISTS (
SELECT *
FROM odwh_work.ead_incident_tp_s wtp
JOIN odwh_data.ead_incident_status_audit_s dis ON wtp.incident = dis.incident AND dis.status IN (6 ,7)
WHERE wtp.incident = dtp.incident
);
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.
I have a bunch of subqueries that each return a bunch of records with two ID fields. I need to return a list of all ID pairs that exist in all subqueries. I was thinking I could do something like this:
SELECT Q1.V1, Q1.V2
FROM ( [SUBQUERY1] ) AS Q1
INNER JOIN ( [SUBQUERY2] ) AS Q2 ON Q2.V1 = Q1.V1 AND Q2.V2 = Q1.V2
INNER JOIN ( [SUBQUERY3] ) AS Q3 ON Q3.V1 = Q2.V1 AND Q3.V2 = Q2.V2
INNER JOIN ( [SUBQUERY4] ) AS Q4 ON Q4.V1 = Q3.V1 AND Q4.V2 = Q3.V2
Is there a better way?
Apparently the answer is to use INTERSECT:
[SUBQUERY1]
INTERSECT
[SUBQUERY2]
INTERSECT
[SUBQUERY3]
INTERSECT
[SUBQUERY4]
Nice!
Intersect is probably better but you can also use group by along with HAVING COUNT(*) > number_of_subqueries clause.
select V1, V2
from
(
(subquery_1)
union
(subquery_2)
union
(subquery_3)
)
group by v1, v2
having count(*) > 3
Suppose I have this query
SELECT * FROM (
SELECT * FROM table_a
WHERE id > 10 )
AS a_results LEFT JOIN
(SELECT * from table_b
WHERE id IN
(SElECT id FROM a_results)
ON (a_results.id = b_results.id)
I would get the error "a_results is not a table". Anywhere I could use the re-use the results of the subquery?
Edit: It has been noted that this query doesn't make sense...it doesn't, yes. This is just to illustrate the question which I am asking; the 'real' query actually looks something like this:
SELECT SQL_CALC_FOUND_ROWS * FROM
( SELECT wp_pod_tbl_hotel . *
FROM wp_pod_tbl_hotel, wp_pod_rel, wp_pod
WHERE wp_pod_rel.field_id =12
AND wp_pod_rel.tbl_row_id =1
AND wp_pod.tbl_row_id = wp_pod_tbl_hotel.id
AND wp_pod_rel.pod_id = wp_pod.id
) as
found_hotel LEFT JOIN (
SELECT COUNT(*) as review_count, avg( (
location_rating + staff_performance_rating + condition_rating + room_comfort_rating + food_rating + value_rating
) /6 ) AS average_score, hotelid
FROM (
SELECT r. * , wp_pod_rel.tbl_row_id AS hotelid
FROM wp_pod_tbl_review r, wp_pod_rel, wp_pod
WHERE wp_pod_rel.field_id =11
AND wp_pod_rel.pod_id = wp_pod.id
AND r.id = wp_pod.tbl_row_id
AND wp_pod_rel.tbl_row_id
IN (
SELECT wp_pod_tbl_hotel .id
FROM wp_pod_tbl_hotel, wp_pod_rel, wp_pod
WHERE wp_pod_rel.field_id =12
AND wp_pod_rel.tbl_row_id =1
AND wp_pod.tbl_row_id = wp_pod_tbl_hotel.id
AND wp_pod_rel.pod_id = wp_pod.id
)
) AS hotel_reviews
GROUP BY hotel_reviews.hotelid
ORDER BY average_score DESC
AS sorted_hotel ON (id = sorted_hotel.hotelid)
As you can see, the sub-query which makes up the found_query table is repeated elsewhere downward as another sub-query, so I was hoping to re-use the results
You can not use a sub-query like this.
I'm not sure I understand your query, but wouldn't that be sufficient?
SELECT * FROM table_a a
LEFT JOIN table_b b ON ( b.id = a.id )
WHERE a.id > 10
It would return all rows from table_a where id > 10 and LEFT JOIN rows from table_b where id matches.