I'm going to select those provinces which intersects any railroad. So I do it like this (Using SQL Spatial):
SELECT * FROM ProvinceTable
WHERE (
SELECT count(*)
FROM RailroadTable
WHERE ProvinceTable.Shape.STIntersects(RailroadTable.Shape) > 1
) > 0
But it is not efficient because it has to check the intersection between every single railroad geometry and province geometry in order to calculate the count. However it is better to stop the where clause as soon as every first intersection detected and there is no need to check others. Here is what I mean:
SELECT * FROM ProvinceTable
WHERE (
--return true if this is true for any row in the RailroadTable:
-- "ProvinceTable.Shape.STIntersects(RailroadTable.Shape) > 1"
)
So is there a better way to rewrite this query for such a goal?
EDIT
Surprisingly This query takes the same time and returns no row:
SELECT * FROM ProvinceTable
WHERE EXISTS (
SELECT *
FROM RailroadTable
WHERE ProvinceTable.Shape.STIntersects(RailroadTable.Shape) > 1
)
You want to use exists:
SELECT pt.*
FROM ProvinceTable pt
WHERE EXISTS (SELECT 1
FROM RailroadTable rt
WHERE pt.Shape.STIntersects(rt.Shape) = 1
);
Related
I am trying to use COUNT(DISTINC column) OVER(PARTITION BY column) when I am using COUNT + window function(OVER).
I get an error like the one in the title and can't get it to work.
I have looked into how to deal with this error, but I have not found an example of how to deal with such a complex query as the one below.
I cannot find an example of how to deal with such a complex query as shown below, and I am not sure how to handle it.
The COUNT part of the problem exists on line 65.
How can such a complex query be resolved without slowing down?
WITH RECURSIVE "cte" AS((
SELECT
"videos_productvideocomment"."id",
"videos_productvideocomment"."user_id",
"videos_productvideocomment"."video_id",
"videos_productvideocomment"."parent_id",
"videos_productvideocomment"."text",
"videos_productvideocomment"."commented_at",
"videos_productvideocomment"."edited_at",
"videos_productvideocomment"."created_at",
"videos_productvideocomment"."updated_at",
"videos_productvideocomment"."id" AS "root_id"
FROM
"videos_productvideocomment"
WHERE
(
"videos_productvideocomment"."parent_id" IS NULL
AND "videos_productvideocomment"."video_id" = 'f264433c-c0af-49cc-8b40-84453da71b2d'
)
) UNION(
SELECT
"videos_productvideocomment"."id",
"videos_productvideocomment"."user_id",
"videos_productvideocomment"."video_id",
"videos_productvideocomment"."parent_id",
"videos_productvideocomment"."text",
"videos_productvideocomment"."commented_at",
"videos_productvideocomment"."edited_at",
"videos_productvideocomment"."created_at",
"videos_productvideocomment"."updated_at",
"cte"."root_id" AS "root_id"
FROM
"videos_productvideocomment"
INNER JOIN
"cte"
ON "videos_productvideocomment"."parent_id" = "cte"."id"
))
SELECT
*,
EXISTS(
SELECT
(1) AS "a"
FROM
"videos_productvideolikecomment" U0
WHERE
(
U0."comment_id" = t."id"
AND U0."user_id" = '3bd3bc86-0335-481e-9fd2-eb2fb1168f48'
)
LIMIT 1
) AS "liked"
FROM
(
SELECT DISTINCT
"cte"."id",
"cte"."created_at",
"cte"."updated_at",
"cte"."user_id",
"cte"."text",
"cte"."commented_at",
"cte"."edited_at",
"cte"."parent_id",
"cte"."video_id",
"cte"."root_id" AS "root_id",
COUNT(DISTINCT "cte"."root_id") OVER(PARTITION BY "cte"."root_id") AS "reply_count", <--- here
COUNT("videos_productvideolikecomment"."id") OVER(PARTITION BY "cte"."id") AS "liked_count"
FROM
"cte"
LEFT OUTER JOIN
"videos_productvideolikecomment"
ON (
"cte"."id" = "videos_productvideolikecomment"."comment_id"
)
) t
WHERE
t."id" = t."root_id"
ORDER BY
CASE
WHEN t."user_id" = '3bd3bc86-0335-481e-9fd2-eb2fb1168f48' THEN 0
ELSE 1
END ASC,
"liked_count" DESC
DISTINCT will look for duplicates and remove it, but in big data it will take a lot of time to process this query, you should process the middle of the record in the programming part I think it will be fast than. Thank
I have a list and the returned table looks like this. I took the preview of only one car but there are many more.
What I need to do now is check that the current KM value is larger then the previous and smaller then the next. If this is not the case I need to make a field called Trustworthy and should fill it with either 1 or 0 (true/ false).
The result that I have so far is this:
validKMstand and validkmstand2 are how I calculate it. It did not work in one list so that is why I separated it.
In both of my tries my code does not work.
Here is the code that I have so far.
FullList as (
SELECT
*
FROM
eMK_Mileage as Mileage
)
, ValidChecked1 as (
SELECT
UL1.*,
CASE WHEN EXISTS(
SELECT TOP(1)UL2.*
FROM FullList AS UL2
WHERE
UL2.FK_CarID = UL1.FK_CarID AND
UL1.KM_Date > UL2.KM_Date AND
UL1.KM > UL2.KM
ORDER BY UL2.KM_Date DESC
)
THEN 1
ELSE 0
END AS validkmstand
FROM FullList as UL1
)
, ValidChecked2 as (
SELECT
List1.*,
(CASE WHEN List1.KM > ulprev.KM
THEN 1
ELSE 0
END
) AS validkmstand2
FROM ValidChecked1 as List1 outer apply
(SELECT TOP(1)UL3.*
FROM ValidChecked1 AS UL3
WHERE
UL3.FK_CarID = List1.FK_CarID AND
UL3.KM_Date <= List1.KM_Date AND
List1.KM > UL3.KM
ORDER BY UL3.KM_Date DESC) ulprev
)
SELECT * FROM ValidChecked2 order by FK_CarID, KM_Date
Maybe something like this is what you are looking for?
;with data as
(
select *, rn = row_number() over (partition by fk_carid order by km_date)
from eMK_Mileage
)
select
d.FK_CarID, d.KM, d.KM_Date,
valid =
case
when (d.KM > d_prev.KM /* or d_prev.KM is null */)
and (d.KM < d_next.KM /* or d_next.KM is null */)
then 1 else 0
end
from data d
left join data d_prev on d.FK_CarID = d_prev.FK_CarID and d_prev.rn = d.rn - 1
left join data d_next on d.FK_CarID = d_next.FK_CarID and d_next.rn = d.rn + 1
order by d.FK_CarID, d.KM_Date
With SQL Server versions 2012+ you could have used the lag() and lead() analytical functions to access the previous/next rows, but in versions before you can accomplish the same thing by numbering rows within partitions of the set. There are other ways too, like using correlated subqueries.
I left a couple of conditions commented out that deal with the first and last rows for every car - maybe those should be considered valid is they fulfill only one part of the comparison (since the previous/next rows are null)?
I am writing down a view in SQL server (DWH) and the use case pseudo code is:
-- Do some calculation and generate #Temp1
-- ... contains other selects
-- Select statement 1
SELECT * FROM Foo
JOIN #Temp1 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1
-- Do some calculation and generate #Temp2
-- ... contains other selects
-- Select statement 2
SELECT * FROM Foo
JOIN #Temp2 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1
The result of the view should be:
Select Statement 1
UNION
Select Statement 2
The intended behavior is the same as the yield returnin C#. Is there a way to tell the view which SELECT statements are actually part of the result and which are not? since the small calculations preceding what I need also contain selects.
Thank you!
Yield return in C# returns rows one at a time as they appear in some underlying function. This concept does not exist in SQL statements. SQl is set-based, returning the entire result set, conceptually as a unit. (That said, sometimes queries run slowly and you will see rows returned slowly or in batches.)
You can control the number of rows being returns using TOP (in SQL Server). You can select particular rows to be returned using WHERE statements. However, you cannot specify a UNION statement that conditionally returns rows from some components but not others.
The closest you may be able to come is something like:
if UseTable1Only = 'Y'
select *
from Table1
else if UseTable2Only = 'Y'
select *
from Table2
else
select *
from table1
union
select *
from table2
You can do something similar using dynamic SQL, by constructing the statement as a string and then executing it.
I found a better work around. It might be helpful for someone else. It is actually to include all the calculation inside WITH statements instead of doing them in the view core:
WITH Temp1 (ID)
AS
(
-- Do some calculation and generate #Temp1
-- ... contains other selects
)
, Temp2 (ID)
AS
(
-- Do some calculation and generate #Temp2
-- ... contains other selects
)
-- Select statement 1
SELECT * FROM Foo
JOIN Temp1 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1
UNION
-- Select statement 2
SELECT * FROM Foo
JOIN Temp2 tmp on tmp.ID = Foo.ID
WHERE Foo.Deleted = 1
The result will be of course the UNION of all the outiside SELECT statements.
I have a sql query that I run against a sql server database eg.
SELECT * FROM MyTable WHERE Id = 2
This may return a number of records or may return none. If it returns none, I would like to alter my sql query to return a default record, is this possible and if so, how? If records are returned, the default record should not be returned. I cannot update the data so will need to alter the sql query for this.
Another way (you would get an empty initial rowset returned);
SELECT * FROM MyTable WHERE Id = 2
IF (##ROWCOUNT = 0)
SELECT ...
SELECT TOP 1 * FROM (
SELECT ID,1 as Flag FROM MyTable WHERE Id = 2
UNION ALL
SELECT 1,2
) qry
ORDER BY qry.Flag ASC
You can have a look to this post. It is similar to what you are asking
Return a value if no rows are found SQL
I hope that it can guide you to the correct path.
if not exists (SELECT top 1 * FROM mytable WHERE id = 2)
select * from mytable where id= 'whatever_the_default_id_is'
else
select * from mytable where id = 2
If you have to return whole rows of data (and not just a single column) and you have to create a single SQL query then do this:
Left join actual table to defaults single-row table
select
coalesce(a.col1, d.col1) as col1,
coalesce(a.col2, d.col2) as col2,
...
from (
-- your defaults record
select
default1 as col1,
default2 as col2,
...) as d
left join actual as a
on ((1 = 1) /* or any actual table "where" conditions */)
The query need to return the same number of fields, so you shouldn't do a SELECT * FROM but a SELECT value FROM if you want to return a default value.
With that in mind
SELECT value FROM MyTable WHERE Id = 2
UNION
SELECT CASE (SELECT count(*) FROM MyTable WHERE Id = 2)
WHEN 0 THEN 'defaultvalue'
END
I need to find a select statement that will return either a record that matches my input exactly, or the closest match if an exact match is not found.
Here is my select statement so far.
SELECT * FROM [myTable]
WHERE Name = 'Test' AND Size = 2 AND PType = 'p'
ORDER BY Area DESC
What I need to do is find the closest match to the 'Area' field, so if my input is 1.125 and the database contains 2, 1.5, 1 and .5 the query will return the record containing 1.
My SQL skills are very limited so any help would be appreciated.
get the difference between the area and your input, take absolute value so always positive, then order ascending and take the first one
SELECT TOP 1 * FROM [myTable]
WHERE Name = 'Test' and Size = 2 and PType = 'p'
ORDER BY ABS( Area - #input )
something horrible, along the lines of:
ORDER BY ABS( Area - 1.125 ) ASC LIMIT 1
Maybe?
If you have many rows that satisfy the equality predicates on Name, Size, and PType columns then you may want to include range predicates on the Area column in your query. If the Area column is indexed this could allow efficient index-based access.
The following query (written using Oracle syntax) uses one branch of a UNION ALL to find the record with minimal Area >= your target, while the other branch finds the record with maximal Area < your target. One of these two records will be the record that you are looking for. Then you can ORDER BY ABS(Area - ?input) to pick the winner out of those two candidates. Unfortunately the query is complex due to nested SELECTS that are needed to enforce the desired ROWNUM / ORDER BY precedence.
SELECT *
FROM
(SELECT * FROM
(SELECT * FROM
(SELECT * FROM [myTable]
WHERE Name = 'Test' AND Size = 2 AND PType = 'p' AND Area >= ?target
ORDER BY Area)
WHERE ROWNUM < 2
UNION ALL
SELECT * FROM
(SELECT * FROM [myTable]
WHERE Name = 'Test' AND Size = 2 AND PType = 'p' AND Area < ?target
ORDER BY Area DESC)
WHERE ROWNUM < 2)
ORDER BY ABS(Area - ?target))
WHERE rownum < 2
A good index for this query would be (Name, Size, PType, Area), in which case the expected query execution plan would be based on two index range scans that each returned a single row.
SELECT *
FROM [myTable]
WHERE Name = 'Test' AND Size = 2 AND PType = 'p'
ORDER BY ABS(Area - 1.125)
LIMIT 1
-- MarkusQ
How about ordering by the difference between your input and [Area], such as:
DECLARE #InputValue DECIMAL(7, 3)
SET #InputValue = 1.125
SELECT TOP 1 * FROM [myTable]
WHERE Name = 'Test' AND Size = 2 AND PType = 'p'
ORDER BY ABS(#InputValue - Area)
Note that although ABS() is supported by pretty much everything, it's not technically standard (in SQL99 at least). If you must write ANSI standard SQL for some reason, you'd have to work around the problem with a CASE operator:
SELECT * FROM myTable
WHERE Name='Test' AND Size=2 AND PType='p'
ORDER BY CASE Area>1.125 WHEN 1 THEN Area-1.125 ELSE 1.125-Area END
If using MySQL
SELECT * FROM [myTable] ... ORDER BY ABS(Area - SuppliedValue) LIMIT 1