Related
I am trying to use a pre-existing table in the SQL statement at the bottom of the question rather than the data that is being generated in the SQL statement. Currently, there is some data that is generated using:
WITH polys(poly_id, geom) AS (VALUES (1, 'POLYGON((1 1, 1 5, 4 5, 4 4, 2 4, 2 2, 4 2, 4 1, 1 1))'::GEOMETRY),
(2, 'POLYGON((6 6, 6 10, 8 10, 9 7, 8 6, 6 6))'::GEOMETRY)),
However, let's say I already have a table named polys with the poly_id and geom columns, exactly as what would be created above. How can I insert my pre-existing polys table into this SQL statement (i.e. what syntax would I use)?
I have tried the following to add a pre-existing polys table using:
CREATE TABLE polys_pts AS
WITH polys(poly_id, geom) AS,
with the following error:
ERROR: syntax error at or near ","
LINE 2: WITH polys(poly_id, geom) AS,
^
Full Code:
CREATE TABLE polys_pts AS
WITH polys(poly_id, geom) AS (VALUES (1, 'POLYGON((1 1, 1 5, 4 5, 4 4, 2 4, 2 2, 4 2, 4 1, 1 1))'::GEOMETRY),
(2, 'POLYGON((6 6, 6 10, 8 10, 9 7, 8 6, 6 6))'::GEOMETRY)),
pnt_clusters AS (SELECT polys.poly_id,
CASE
WHEN ST_Area(polys.geom)>9 THEN ST_ClusterKMeans(pts.geom, 8) OVER(PARTITION BY polys.poly_id)
ELSE ST_ClusterKMeans(pts.geom, 2) OVER(PARTITION BY polys.poly_id)
END AS cluster_id, pts.geom FROM polys,
LATERAL ST_Dump(ST_GeneratePoints(polys.geom, 1000, 1)) AS pts),
centroids AS (SELECT cluster_id, ST_PointOnSurface(ST_collect(geom)) AS geom FROM pnt_clusters GROUP BY poly_id, cluster_id),
neg_buffer AS (SELECT poly_id, (ST_Buffer(geom, -0.4, 'endcap=flat join=round')) geom FROM polys GROUP BY poly_id, polys.geom),
neg_buffer_pts_out AS (SELECT a.cluster_id, (a.geom) geom FROM centroids a WHERE EXISTS (SELECT 1 FROM neg_buffer b WHERE ST_Intersects(a.geom, b.geom))),
neg_buffer_pts_in AS (SELECT a.cluster_id, (a.geom) geom FROM centroids a WHERE NOT EXISTS (SELECT 1 FROM neg_buffer b WHERE ST_Intersects(a.geom, b.geom))),
snap_pts_clusters_in AS (SELECT DISTINCT ST_ClosestPoint(ST_ExteriorRing(a.geom), b.geom) AS geom FROM neg_buffer a, neg_buffer_pts_in b),
node_pts AS (SELECT ST_StartPoint(ST_ExteriorRing(geom)) geom FROM neg_buffer),
snap_pts AS (SELECT b.cluster_id, a.geom FROM snap_pts_clusters_in a JOIN centroids b ON ST_DWithin(a.geom, b.geom, 0.4))
SELECT a.cluster_id, (a.geom) geom FROM snap_pts a WHERE NOT EXISTS (SELECT 1 FROM node_pts b WHERE ST_Intersects(a.geom, b.geom))
UNION SELECT c.cluster_id, (c.geom) geom FROM neg_buffer_pts_out c ORDER BY cluster_id;
I'm not sure of understanding your question so i give you a broad answer.
To create a table from a query you must use:
CREATE TABLE foo AS
SELECT * FROM my_table;
CTEs are builded as:
WITH
tmp1 AS (
SELECT * from my_table1
), -- commna
tmp2 AS (
SELECT * from my_table2
)
SELECT * from tmp1 JOIN tmp2 ON tmp1.id = tmp2.id -- no comma
;
Note that the are , to separate different "temporary" tables defined in the CTE but the final sentence is not preceded with a ,
So to create a table from a CTE the syntax will be:
CREATE TABLE foo AS
WITH
tmp1 AS (
SELECT * from my_table1
),
tmp2 AS (
SELECT * from my_table2
)
SELECT * from tmp1 JOIN tmp2 ON tmp1.id = tmp2.id -- no comma
;
Create a table from a VALUES clause is the same as the other cases:
CREATE TABLE polys2 AS
VALUES
(1, 'POLYGON((1 1, 1 5, 4 5, 4 4, 2 4, 2 2, 4 2, 4 1, 1 1))'::GEOMETRY),
(2, 'POLYGON((6 6, 6 10, 8 10, 9 7, 8 6, 6 6))'::GEOMETRY)
;
If you already have a table called polys2 that has been created for example like is shown in the previous example, you can replace
CREATE TABLE polys_pts AS
WITH
polys(poly_id, geom) AS (
VALUES
(1, 'POLYGON((1 1, 1 5, 4 5, 4 4, 2 4, 2 2, 4 2, 4 1, 1 1))'::GEOMETRY),
(2, 'POLYGON((6 6, 6 10, 8 10, 9 7, 8 6, 6 6))'::GEOMETRY)),
pnt_clusters AS (SELECT polys.poly_id, ...
with
CREATE TABLE polys_pts AS
WITH
polys(poly_id, geom) AS (
SELECT poly_id, geom FROM polys2
),
pnt_clusters AS (SELECT polys.poly_id, ...
um, the question is not 100% clear to me - ... I am not familiar with pecularities of postgresql, but my first bet would be to try
WITH polys(...) AS (...),
pnt_clusters AS (...)
CREATE polys_pts AS (
SELECT ..
FROM polys... etc.
)
but I guess this is not allowed since WITH only goes with DML statements (data manipulation unlike data definition (DDL) statements like CREATE)
so.. my next bet would be to try using polys and pnt_clusters that you defined inside WITH clause, inline inside the SELECT statement, given that
WITH a AS (
SELECT x, y FROM z
)
SELECT *
FROM a
is the same as
SELECT *
FROM (
SELECT x, y
FROM z
) AS a
well, otherwise I would split the process into two steps - create some kind of temporary tables first for polys and pnt_clusters and then do the create...
The definition of a CTE must be a complete statement, so you have to use
WITH polys(poly_id, geom) AS (
SELECT *
FROM (VALUES
(1, 'POLYGON((1 1, 1 5, 4 5, 4 4, 2 4, 2 2, 4 2, 4 1, 1 1))'::GEOMETRY),
(2, 'POLYGON((6 6, 6 10, 8 10, 9 7, 8 6, 6 6))'::GEOMETRY)
) AS p(p, g)
)
I am looking at different breeds of cattle and their AnimalTypeCode , BreedCateoryID and resultant Growth.
I have the following query
SELECT DATEPART(yyyy,[KillDate])
,[AnimalTypeCode]
,AVG([Growth])
,[BreedCategoryID]
FROM [dbo].[tblAnimal]
WHERE (AnimalTypeCode='C'
or AnimalTypeCode= 'E')
GROUP BY DATEPART(yyyy,[KillDate])
,[AnimalTypeCode]
,[BreedCategoryID]
GO
This query is good and gives me almost what I want, but BreedCategoryID is numbered 1 through 7 and I would like to group them:
(1 = Pure Dairy),
(2 and 3 = Dairy)
(4, 5, 6 and 7 = Beef)
So instead of getting the mean Growthrate for each BreedCategoryID I would like to get the average for Pure Dairy, Dairy, and Beef.
Any help greatly appreciated!
You can assign a new "variable" using cross apply in the from clause:
SELECT YEAR(KillDate]), a.AnimalTypeCode, v.grp,
AVG([Growth])
FROM [dbo].[tblAnimal] a CROSS APPLY
(VALUES (CASE WHEN a.BreedCategoryID IN (1) THEN 'Pure Dairy'
WHEN a.BreedCategoryID IN (2, 3) THEN 'Dairy'
WHEN a.BreedCategoryID IN (4, 5, 6, 7) THEN 'Beef'
END)
) as v(grp)
WHERE a.AnimalTypeCode IN ('C', 'E')
GROUP BY YEAR(KillDate]), a.AnimalTypeCode, v.grp;
Note that I also introduced table aliases and qualified all the column references.
Do the calculations in a derived table (the subquery). GROUP BY its result:
select killyear, [AnimalTypeCode], AVG([Growth]), BreedCat
(
SELECT DATEPART(yyyy,[KillDate]) killyear
,[AnimalTypeCode]
,[Growth]
,case when [BreedCategoryID] = 1 then 'Pure Dairy'
when [BreedCategoryID] in (2, 3) then 'Dairy'
when [BreedCategoryID] in (4, 5, 6, 7) then 'Beef'
end BreedCat
FROM [dbo].[tblAnimal]
WHERE (AnimalTypeCode='C'
or AnimalTypeCode= 'E')
) dt
GROUP BY killyear
,[AnimalTypeCode]
,BreedCat
How can I exclude matched elements of one array from another?
Postgres code:
a1 := '{1, 2, 5, 15}'::int[];
a2 := '{1, 2, 3, 6, 7, 9, 15}'::int[];
a3 := a2 ??magic_operator?? a1;
In a3 I expect exactly '{3, 6, 7, 9}'
Final Result
My and lad2025 solutions works fine.
Solution with array_position() required PostgreSQL 9.5 and later, executes x3 faster.
It looks like XOR between arrays:
WITH set1 AS
(
SELECT * FROM unnest('{1, 2, 5, 15}'::int[])
), set2 AS
(
SELECT * FROM unnest('{1, 2, 3, 6, 7, 9, 15}'::int[])
), xor AS
(
(SELECT * FROM set1
UNION
SELECT * FROM set2)
EXCEPT
(SELECT * FROM set1
INTERSECT
SELECT * FROM set2)
)
SELECT array_agg(unnest ORDER BY unnest)
FROM xor
Output:
"{3,5,6,7,9}"
How it works:
Unnest both arrays
Calculate SUM
Calculate INTERSECT
From SUM - INTERSECT
Combine to array
Alternatively you could use sum of both minus(except) operations:
(A+B) - (A^B)
<=>
(A-B) + (B-A)
Utilizing FULL JOIN:
WITH set1 AS
(
SELECT *
FROM unnest('{1, 2, 5, 15}'::int[])
), set2 AS
(
SELECT *
FROM unnest('{1, 2, 3, 6, 7, 9, 15}'::int[])
)
SELECT array_agg(COALESCE(s1.unnest, s2.unnest)
ORDER BY COALESCE(s1.unnest, s2.unnest))
FROM set1 s1
FULL JOIN set2 s2
ON s1.unnest = s2.unnest
WHERE s1.unnest IS NULL
OR s2.unnest IS NULL;
EDIT:
If you want only elements from second array that are not is first use simple EXCEPT:
SELECT array_agg(unnest ORDER BY unnest)
FROM (SELECT * FROM unnest('{1, 2, 3, 6, 7, 9, 15}'::int[])
EXCEPT
SELECT * FROM unnest('{1, 2, 5, 15}'::int[])) AS sub
Output:
"{3,6,7,9}"
The additional module intarray provides a simple and fast subtraction operator - for integer arrays, exactly the magic_operator you are looking for:
test=# SELECT '{1, 2, 3, 6, 7, 9, 15}'::int[] - '{1, 2, 5, 15}'::int[] AS result;
?column?
-----------
{3,6,7,9}
You need to install the module once per database:
CREATE EXTENSION intarray;
It also provides special operator classes for indexes:
Postgresql intarray error: undefined symbol: pfree
Note that it only works for:
... null-free arrays of integers.
I found a little similar case and modify.
That SQL solve my case.
with elements (element) as (
select unnest(ARRAY[1, 2, 3, 6, 7, 9, 15])
)
select array_agg(element)
from elements
where array_position(ARRAY[1, 2, 5, 15],element) is null
PostgreSQL 9.5 and later required.
Suppose I have a table(a relationship) like
MyTab(ID1,ID2,IsMarked, data,....)
the sample data maybe looks like:
1, 1, 1, ...
1, 2, 0, ...
1, 3, 0, ...
2, 34, 1, ...
3, 4, 0, ...
4, 546, 0, ...
4, 8, 0, ...
Only one could be marked for each ID1. I want to get data marked as 1 for all Entities ID1. If there is no marked record, get the first one or any one of them.
For above sample data, the result should be:
1, 1, 1, ...
2, 34, 1, ...
3, 4, 0, ...
4, 546, 0, ...
Union could be a solution, but is too long and may have bad performance.
My idea is to sort the data by ID1 and IsMarked desc, the get the first 1 for each ID1, but how to write a SQL for this case?
For Only one could be marked for each ID1 the following should work:
;with cte as (
select *, rn=row_number() over (partition by ID1 order by IsMarked desc)
)
select *
from cte
where rn=1
Shot in the dark:
SELECT A.*
FROM MYTAB A
LEFT JOIN (
SELECT MAX(ID2) AS MAXID2, ID1
FROM MYTAB
WHERE ISMARKED=1
GROUP BY ID1
) B ON A.ID2=B.MAXID2 AND A.ID1=B.ID1
LEFT JOIN (
SELECT MAX(ID2) AS MAXID2, ID1
FROM MYTAB
WHERE ISMARKED=0
GROUP BY ID1
) C ON A.ID2=C.MAXID2 AND A.ID1=C.ID1
WHERE
(B.ID1 IS NOT NULL)
OR
(B.ID1 IS NULL AND C.ID1 IS NOT NULL);
How can I limit a result set to n distinct values of a given column(s), where the actual number of rows may be higher?
Input table:
client_id, employer_id, other_value
1, 2, abc
1, 3, defg
2, 3, dkfjh
3, 1, ldkfjkj
4, 4, dlkfjk
4, 5, 342
4, 6, dkj
5, 1, dlkfj
6, 1, 34kjf
7, 7, 34kjf
8, 6, lkjkj
8, 7, 23kj
desired output, where limit distinct=5 distinct values of client_id:
1, 2, abc
1, 3, defg
2, 3, dkfjh
3, 1, ldkfjkj
4, 4, dlkfjk
4, 5, 342
4, 6, dkj
5, 1, dlkfj
Platform this is intended for is MySQL.
You can use a subselect
select * from table where client_id in
(select distinct client_id from table order by client_id limit 5)
This is for SQL Server. I can't remember, MySQL may use a LIMIT keyword instead of TOP. That may make the query more efficient if you can get rid of the inner most subquery by using the LIMIT and DISTINCT in the same subquery. (It looks like Vinko used this method and that LIMIT is correct. I'll leave this here for the second possible answer though.)
SELECT
client_id,
employer_id,
other_value
FROM
MyTable
WHERE
client_id IN
(
SELECT TOP 5
client_id
FROM
(
SELECT DISTINCT
client_id
FROM
MyTable
) SQ
ORDER BY
client_id
)
Of course, add in your own WHERE clause and ORDER BY clause in the subquery.
Another possibility (compare performance and see which works out better) is:
SELECT
client_id,
employer_id,
other_value
FROM
MyTable T1
WHERE
T1.code IN
(
SELECT
T2.code
FROM
MyTable T2
WHERE
(SELECT COUNT(*) FROM MyTable T3 WHERE T3,code < T2.code) < 5
)
-- Using Common Table Expression in Microsoft SQL Server.
-- LIMIT function does not exist in MS SQL.
WITH CTE
AS
(SELECT DISTINCT([COLUMN_NAME])
FROM [TABLE_NAME])
SELECT TOP (5) [[COLUMN_NAME]]
FROM CTE;
This works for MS SQL if anyone is on that platform:
SET ROWCOUNT 10;
SELECT DISTINCT
column1, column2, column3,...
FROM
Table1
WHERE ...