Let's sat I have a Table 'A' with rows:
A
B
C
D
Is there a simple way to do a cross join that creates
A 1
A 2
A 3
A 4
...
D 1
D 2
D 3
D 4
without creating a second table?
Something like:
SELECT *
FROM A
CROSS JOIN (1,2,3,4)
something like that should work, i guess
select * from A cross join (select 1 union all select 2 union all select 3 union all select 4) as tmp
you will create a second table, but you won't persist it.
The following would work for a table of any size (though I only tested it against 6 rows). It uses the ranking functions available in SQL Server 2005 and up, but the idea should be adaptible to any RDBMS.
SELECT ta.SomeColumn, cj.Ranking
from TableA ta
cross join (select row_number() over (order by SomeColumn) Ranking from TableA) cj
order by ta.SomeColumn, cj.Ranking
You should be able to achieve this via
select * from A cross join
(select 1
union all
select 2
union all
select 3
union all
select 4)
Related
In my postgres table, I have two columns of interest: id and name - my goal is to only keep records where id has more than one value in name. In other words, would like to keep all records of ids that have multiple values and where at least one of those values is B
UPDATE: I have tried adding WHERE EXISTS to the queries below but this does not work
The sample data would look like this:
> test
id name
1 1 A
2 2 A
3 3 A
4 4 A
5 5 A
6 6 A
7 7 A
8 2 B
9 1 B
10 2 B
and the output would look like this:
> output
id name
1 1 A
2 2 A
8 2 B
9 1 B
10 2 B
How would one write a query to select only these kinds records?
Based on your description you would seem to want:
select id, name
from (select t.*, min(name) over (partition by id) as min_name,
max(name) over (partition by id) as max_name
from t
) t
where min_name < max_name;
This can be done using EXISTS:
select id, name
from test t1
where exists (select *
from test t2
where t1.id = t2.id
and t1.name <> t2.name) -- this will select those with multiple names for the id
and exists (select *
from test t3
where t1.id = t3.id
and t3.name = 'B') -- this will select those with at least one b for that id
Those records where for their id more than one name shines up, right?
This could be formulated in "SQL" as follows:
select * from table t1
where id in (
select id
from table t2
group by id
having count(name) > 1)
How would I go about using the result of a recursive CTE in a query I plan to run with Ecto? For example let's say I have a table, nodes, structured as so:
-- nodes table example --
id parent_id
1 NULL
2 1
3 1
4 1
5 2
6 2
7 3
8 5
and I also have another table nodes_users structured as so:
-- nodes_users table example --
node_id user_id
1 1
2 2
3 3
5 4
Now, I want to grab all the users with a node at or above a specific node, for the sake of an example let's choose the node w/ the id 8.
I could use the following recursive postgresql query to do so:
WITH RECURSIVE nodes_tree AS (
SELECT *
FROM nodes
WHERE nodes.id = 8
UNION ALL
SELECT n.*
FROM nodes n
INNER JOIN nodes_tree nt ON nt.parent_id = n.id
)
SELECT u.* FROM users u
INNER JOIN users_nodes un ON un.user_id = u.id
INNER JOIN nodes_tree nt ON nt.id = un.node_id
This should return users.* for the users w/ id of 1, 2, and 4.
I'm not sure how I could run this same query using ecto, ideally in a manner that would return a chainable output. I understand that I can insert raw SQL into my query using the fragment macro, but I'm not exactly sure where that would go for this use or if that would even be the most appropriate route to take.
Help and/or suggestions would be appreciated!
I was able to accomplish this using a fragment. Here's an example of the code I used. I'll probably move this method to a stored procedure.
Repo.all(MyProj.User,
from u in MyProj.User,
join: un in MyProj.UserNode, on: u.id == un.user_id,
join: nt in fragment("""
(
WITH RECURSIVE node_tree AS (
SELECT *
FROM nodes
WHERE nodes.id = ?
UNION ALL
SELECT n.*
FROM nodes n
INNER JOIN node_tree nt ON nt.parent_id == n.id
)
) SELECT * FROM node_tree
""", ^node_id), on: un.node_id == nt.id
)
I am stuck at this T-SQL query.
I have table below
Age SectioName Cost
---------------------
1 Section1 100
2 Section1 200
1 Section2 500
3 Section2 100
4 Section2 200
Lets say for each section I can have maximum 5 Age. In above table there are some missing Ages. How do I insert missing Ages for each section. (Possibly without using cursor). The cost would be zero for missing Ages
So after the insertion the table should look like
Age SectioName Cost
---------------------
1 Section1 100
2 Section1 200
3 Section1 0
4 Section1 0
5 Section1 0
1 Section2 500
2 Section2 0
3 Section2 100
4 Section2 200
5 Section2 0
EDIT1
I should have been more clear with my question. The maximum age is dynamic value. It could be 5,6,10 or someother value but it will be always less than 25.
I think I got it
;WITH tally AS
(
SELECT 1 AS r
UNION ALL
SELECT r + 1 AS r
FROM tally
WHERE r < 5 -- this value could be dynamic now
)
select n.r, t.SectionName, 0 as Cost
from (select distinct SectionName from TempFormsSectionValues) t
cross join
(select ta.r FROM tally ta) n
where not exists
(select * from TempFormsSectionValues where YearsAgo = n.r and SectionName = t.SectionName)
order by t.SectionName, n.r
You can use this query to select missing value:
select n.num, t.SectioName, 0 as Cost
from (select distinct SectioName from table1) t
cross join
(select 1 as num union select 2 union select 3 union select 4 union select 5) n
where not exists
(select * from table1 where table1.age = n.num and table1.SectioName = t.SectioName)
It creates a Cartesian product of sections and numbers 1 to 5 and then selects those that doesn't exist yet. You can then use this query for the source of insert into your table.
SQL Fiddle (it has order by added to check the results easier but it's not necessary for inserting).
Use below query to generate missing rows
SELECT t1.Age,t1.Section,ISNULL(t2.Cost,0) as Cost
FROM
(
SELECT 1 as Age,'Section1' as Section,0 as Cost
UNION
SELECT 2,'Section1',0
UNION
SELECT 3,'Section1',0
UNION
SELECT 4,'Section1',0
UNION
SELECT 5,'Section1',0
UNION
SELECT 1,'Section2',0
UNION
SELECT 2,'Section2',0
UNION
SELECT 3,'Section2',0
UNION
SELECT 4,'Section2',0
UNION
SELECT 5,'Section2',0
) as t1
LEFT JOIN test t2
ON t1.Age=t2.Age AND t1.Section=t2.Section
ORDER BY Section,Age
SQL Fiddle
You can utilize above result set for inserting missing rows by using EXCEPT operator to exclude already existing rows in table -
INSERT INTO test
SELECT t1.Age,t1.Section,ISNULL(t2.Cost,0) as Cost
FROM
(
SELECT 1 as Age,'Section1' as Section,0 as Cost
UNION
SELECT 2,'Section1',0
UNION
SELECT 3,'Section1',0
UNION
SELECT 4,'Section1',0
UNION
SELECT 5,'Section1',0
UNION
SELECT 1,'Section2',0
UNION
SELECT 2,'Section2',0
UNION
SELECT 3,'Section2',0
UNION
SELECT 4,'Section2',0
UNION
SELECT 5,'Section2',0
) as t1
LEFT JOIN test t2
ON t1.Age=t2.Age AND t1.Section=t2.Section
EXCEPT
SELECT Age,Section,Cost
FROM test
SELECT * FROM test
ORDER BY Section,Age
http://www.sqlfiddle.com/#!3/d9035/11
Hi I have a CTE with 5 inner joins and a where clause which is reducing by one.
the sample code looks like below. but the actual code has more complex logic
;With CTE_EG AS
(
select *,
-1 as offset from a
inner join a1 on a1.id=a.id
inner join a2 on a1.id=a2.id
inner join a3 on a1.id=a3.id
where a1.offset = a2.quarter-1
union all
select *,
-2 as offset from a
inner join a1 on a1.id=a.id
inner join a2 on a1.id=a2.id
inner join a3 on a1.id=a3.id
where a1.offset = a2.quarter-2
union all
...
)
this repeats till offset -4 and a1.offset = a2.quarter-4.
How can I avoid the same code to be repeated for so many times for only one where clause value. the actualy query has 5 inner joins and total 5 union all.
I can not remove the union all because that will generate in some calculation discrepancy.
I want something like when we pass an integer value n , the selects in between union all should repeat with the changing where clause like a1.offset = a2.quarter-2 to a1.offset = a2.quarter-n
Please suggest
This should just be:
;With Numbers(n) as (
select 1 union all select 2 union all
select 3 union all select 4
), CTE_EG AS
(
select *,
-n as offset from a
inner join a1 on a1.id=a.id
inner join a2 on a1.id=a2.id
inner join a3 on a1.id=a3.id
inner join numbers n on a1.offset = a2.quarter-n
)
I don't understand your point about not being able to remove the UNION ALL.
I have a table with some transaction fields, primary id is a CUSTomer field and a TXN_DATE and for two of them, NOM_AMOUNT and GRS_AMOUNT I need an EndOfMonth SUM (no rolling, just EOM, can be 0 if no transaction in the month) for these two amount fields. How can I do it? I need also a 0 reported for months with no transactions..
Thank you!
If you group by the expresion month(txn_date) you can calculate the sum. If you use a temporary table with a join on month you can determine which months have no records and thus report a 0 (or null if you don't use the coalesce fiunction).
This will be your end result, I assume you are able to add the other column you need to sum and adapt for your schema.
select mnt as month
, sum(coalesce(NOM_AMOUNT ,0)) as NOM_AMOUNT_EOM
, sum(coalesce(GRS_AMOUNT ,0)) as GRS_AMOUNT_EOM
from (
select 1 as mnt
union all select 2
union all select 3
union all select 4
union all select 5
union all select 6
union all select 7
union all select 8
union all select 9
union all select 10
union all select 11
union all select 12) as m
left outer join Table1 as t
on m.mnt = month(txn_date)
group by mnt
Here is the initial working sqlfiddle