I have this table (elev_table) :
country | cat | elev
--------------+-----+----------
USA | 0 | 41.46
USA | 1 | 878.90
USA | 2 | 78.01
CAN | 0 | 46.00
CAN | 1 | 78.92
CAN | 2 | 78.01
CAN | 4 | 667.77
CAN | 5 | 10.80
How can I create a query to return the same table, filled with missing cat values? The cat column has to values from (-1 to 5) but not every country value contains every cat value.
Essentially, for every country in my table I need rows with elevation values for every cat value of -1 to 5.....
For example I want the resulting table to look like:
country | cat | elev
--------------+-----+----------
USA | -1 | 0
USA | 0 | 41.46
USA | 1 | 878.90
USA | 2 | 78.01
USA | 3 | 0
USA | 4 | 0
USA | 5 | 0
CAN | -1 | 0
CAN | 0 | 46.00
CAN | 1 | 78.92
CAN | 2 | 78.01
CAN | 3 | 0
CAN | 4 | 667.77
CAN | 5 | 10.80
I believe 0 would be a good representation, but maybe NULL would be better?
I have tried the following query, but this doesn't create missing row values for each country... I know I am missing something but can't seem to figure out what!!!
with cat_series as(
select generate_series(-1,5) as fullcat
)
select fullcat, coalesce(sum(t.elev),0), t.country
from cat_series
left join elev_table t on cat_series.fullcat=t.cat
group by fullcat, t.country
order by fullcat, t.country;
Still quite new to postgres, sql. Any help or pointers would be appreciated!
You can use a cross join followed by a left join:
select c.country, g.cat, coalesce(sum(t.elev), 0)
from (select distinct country from elev_table) c cross join
generate_series(-1, 5) as g(cat) left join
elev_table et
on et.country = c.country and et.cat = g.cat
group by c.country, g.cat;
I left the group by in the query, although based on the sample data, this is sufficient:
select c.country, g.cat, coalesce(t.elev, 0)
from (select distinct country from elev_table) c cross join
generate_series(-1, 5) as g(cat) left join
elev_table et
on et.country = c.country and et.cat = g.cat;
You can remove the coalesce() if you prefer NULL to 0.
Related
I have three tables store, gender, age_group each of these tables have ids. I need to generate table data for each one all possible combinations of the three.
ex. store_id = (1,2,3) gender_id = (1,2,3) age_group_id = (1,2,3)
so that i have a table that looks like this:
|store_id|gender_id|age_group_id|
|:------:|:-------:|:----------:|
| 1 | 1 | 1 |
| 1 | 2 | 1 |
| 1 | 3 | 1 |
| 2 | 1 | 3 |
| 2 | 2 | 3 |
| 3 | 1 | 3 |
| 3 | 2 | 3 |
etc. continuing on until each combination is populated, any suggestions on best approach to do this in SQL
Cross join the three tables:
select
s.Id as store_id,
g.Id as gender_id,
a.Id as age_group_id
from store s
cross join gender g
cross join age_group a
So I am wondering. I fell into an interesting suggestion from another developer. So i basically have two tables I join in a query and I want the resulting table from the query to have an extra column that comes from the table on from the joint.
Example:
#table A: contains rating of players, changes randomly at any date depending
#on drop of form from the players
PID| Rating | DateChange |
1 | 2 | 10-May-2014 |
1 | 4 | 20-May-2015 |
1 | 20 | 1-June-2015 |
2 | 4 | 1-April-2014|
3 | 4 | 5-April-2014|
2 | 3 | 3-May-2015 |
#Table B: contains match sheets. Every player has a different match sheet
#and plays different dates.
MsID | PID | MatchDate | Win |
1 | 2 | 10-May-2014 | No |
2 | 1 | 15-May-2015 | Yes |
3 | 3 | 10-Apr-2014 | No |
4 | 1 | 21-Apr-2015 | Yes |
5 | 1 | 3-June-2015 | Yes |
6 | 2 | 5-May-2015 | No |
#I am trying to achieve this by running the ms-access query: i want to get
#every players rating at the time the match was played not his current
#rating.
MsID | PID | MatchDate | Rating |
1 | 2 | 10-May-2014 | 4 |
2 | 1 | 15-May-2015 | 2 |
3 | 3 | 10-Apr-2014 | 4 |
4 | 1 | 21-Apr-2015 | 4 |
5 | 1 | 3-June-2015 | 20 |
6 | 2 | 5-May-2015 | 3 |
This is what I have tried below:
Select MsID, PID, MatchDate, A-table.rating as Rating from B-table
left Join A-table
on B-table.PID = A-table.PID
where B-table.MatchDate > A-table.Datechange;
any help is appreciated. The solution can be in Vba as long as it returns something like a view/table I can manipulate using other queries or report.
Think of this in terms of sets of data... you need a set that lists the MAX dateChange for each player's and match date.
Soo...
SELECT MAX(A.DateChange) MDC, A.PID, B.Matchdate
FROM B-table B
INNER Join A-table A
on B.PID = A.PID
and A.DateChange <= B.MatchDate
GROUP BY A.PID, B.Matchdate
Now we take this and join it back to what you've done to limit the results in table A and B to ONLY those with that date player and matchDate (my inline table C)
SELECT B.MsID, B.PID, B.MatchDate, A.rating as Rating
FROM [B-table] B
INNER JOIN [A-table] A
on B.PID = A.PID
INNER JOIN (
SELECT MAX(Y.DateChange) MDC, Y.PID, Z.Matchdate
FROM [B-table] Z
INNER Join [A-table] Y
on Z.PID = Y.PID
and Y.DateChange <= Z.MatchDate
GROUP BY Y.PID, Z.Matchdate) C
on C.mdc = A.DateChange
and A.PID = C.PId
and B.MatchDate = C.Matchdate
I didn't create a sample for this using your data so it's untested but I believe the logic is sound...
Now Tested! SQL Fiddle using SQL server though...
My results don't match yours exactly. I think you're expected results are wrong though for MSID 4 given rules defined.
I have 2 tables , "T_COMMON_COUNTRY" and "T_HEI_STUDENTDATA." using left join I joined these tables
this is my query
SELECT
[T_COMMON_COUNTRY].[COUNTRY_ID],
[T_COMMON_COUNTRY].[COUNTRY],
[T_HEI_STUDENTDATA].[STUDENT_ID]
FROM ([T_COMMON_COUNTRY]
LEFT JOIN [T_HEI_STUDENTDATA]
ON [T_COMMON_COUNTRY].[COUNTRY] = [T_HEI_STUDENTDATA].[STDCOUNTRY])
now I' getting view like this
| Country ID | County | Student ID |
| 1 | USA | 12 |
| 1 | USA | 5 |
| 2 | UK | 11 |
| 2 | UK | 2 |
I want Count the number of students (Student_IDs) relate to a country ,
I want get a view exactly like below
| Country ID | County | Students |
| 1 | USA | 2 |
| 2 | UK | 2 |
Use COUNT function to generate countrywise student count
Try this:
SELECT C.[COUNTRY_ID], C.[COUNTRY], COUNT(S.[STUDENT_ID]) AS StudentCount
FROM [T_COMMON_COUNTRY] C
LEFT JOIN [T_HEI_STUDENTDATA] S ON C.[COUNTRY] = S.[STDCOUNTRY]
GROUP BY C.[COUNTRY_ID], C.[COUNTRY];
Use COUNT function to count the number of students GROUP BY Country_ID and Country.
SELECT
[T_COMMON_COUNTRY].[COUNTRY_ID],
[T_COMMON_COUNTRY].[COUNTRY],
COUNT([T_HEI_STUDENTDATA].[STUDENT_ID]) AS Students
FROM ([T_COMMON_COUNTRY]
LEFT JOIN [T_HEI_STUDENTDATA]
ON [T_COMMON_COUNTRY].[COUNTRY] = [T_HEI_STUDENTDATA].[STDCOUNTRY])
GROUP BY [T_COMMON_COUNTRY].[COUNTRY_ID], [T_COMMON_COUNTRY].[COUNTRY]
I have to make sortable table like this:
Sortable table:
building_id | building_age | title |
-------------------------------------------------
1 | 100 | New york buil |
2 | 50 | House 1 |
3 | 50 | House 10 |
From these tables:
Building Table:
building_id | building_age | building_type_1_FK | building_type_2_FK
---------------------------------------------------------
1 | 100 | null | 1
2 | 50 | 1 | null
3 | 50 | 2 | null
building_type_1:
type_id | title | diff1 |
-------------------------------------------------
1 | New york buil| blablabla |
building_type_2:
building_id | title |
----------------------------
1 | House 1 |
2 | House 10 |
3 | House 500 |
While joining these tables I get several title columns where one of them is not null. Is there any way to sort by title and select top 10 results without fetching all the data and then sorting in the app?
p.s.. I know that in general this architecture is not good, but I can't change it.
Yes. You want to do a left outer join to the two tables, and then bring the results together:
select b.building_id, b.building_age, coalesce(bt1.title, bt2.title) as title
from building b left outer join
building_type_1 bt1
on b.building_type_1_FK = bt1.type_id left outer join
building_type_2 bt2
on b.building_type_2_FK = bt2.building_id;
To get the top 10 results in Oracle:
select *
from (select b.building_id, b.building_age, coalesce(bt1.title, bt2.title) as title
from building b left outer join
building_type_1 bt1
on b.building_type_1_FK = bt1.type_id left outer join
building_type_2 bt2
on b.building_type_2_FK = bt2.building_id
order by title
) b
where rownum <= 10;
I have the following table called Attributes
* AttId * CustomerId * Class * Code *
| 1 | 1 | 1 | AA |
| 2 | 1 | 1 | AB |
| 3 | 1 | 1 | AC |
| 4 | 1 | 2 | AA |
| 5 | 1 | 2 | AB |
| 6 | 1 | 3 | AB |
| 7 | 2 | 1 | AA |
| 8 | 2 | 1 | AC |
| 9 | 2 | 2 | AA |
| 10 | 3 | 1 | AB |
| 11 | 3 | 3 | AB |
| 12 | 4 | 1 | AA |
| 13 | 4 | 2 | AA |
| 14 | 4 | 2 | AB |
| 15 | 4 | 3 | AB |
Where each Class, Code pairing represents a specific Attribute.
I'm trying to write a query that returns all customers that are NOT linked to the Attribute pairing Class = 1, Code = AB.
This would return Customer Id values 2 and 4.
I started to write Select Distinct A.CustomerId From Attributes A Where (A.Class = 1 and A.Code = 'AB') but stopped when I realised I was writing a SQL query and there is not an operator available to place before the parentheses to indicate the clause within must Not be met.
What am I missing? Or which operator should I be looking at?
Edit:
I'm trying to write a query that only returns those Customers (ie distinct Customer Id's) that have NO link to the Attribute pairing Class = 1, Code = AB.
This could only be Customer Id values 2 and 4 as the table does Not contain the rows:
* AttId * CustomerId * Class * Code *
| x | 2 | 1 | AB |
| x | 4 | 1 | AB |
Changed Title from:
How to write "Where Not(a=x and b=x)"in Sql Query
To:
How to write a Sql query to find distinct values that have never met the following "Where Not(a=x and b=x)"
As the previous title was a question in it's own right however the detail of the question added an extra dimension which led to confusion.
One way would be
SELECT DISTINCT CustomerId FROM Attributes a
WHERE NOT EXISTS (
SELECT * FROM Attributes forbidden
WHERE forbidden.CustomerId = a.CustomerId AND forbidden.Class = _forbiddenClassValue_ AND forbidden.Code = _forbiddenCodeValue_
)
or with join
SELECT DISTINCT a.CustomerId FROM Attributes a
LEFT JOIN (
SELECT CustomerId FROM Attributes
WHERE Class = _forbiddenClassValue_ AND Code = _forbiddenCodeValue_
) havingForbiddenPair ON a.CustomerId = havingForbiddenPair.CustomerId
WHERE havingForbiddenPair.CustomerId IS NULL
Yet another way is to use EXCEPT, as per ypercube's answer
SELECT CustomerId
FROM Attributes
EXCEPT
SELECT CustomerId
FROM Attributes
WHERE Class = 1
AND Code = AB ;
Since no one has posted the simple logical statement, here it is:
select . . .
where A.Class <> 1 OR A.Code <> 'AB'
The negative of (X and Y) is (not X or not Y).
I see, this is a grouping thing. For this, you use aggregation and having:
select customerId
from Attributes a
group by CustomerId
having sum(case when A.Class = 1 and A.Code = 'AB' then 1 else 0 end) = 0
I always prefer to solve "is it in a set" type questions using this technique.
Select Distinct A.CustomerId From Attributes A Where not (A.Class = 1 and A.Code = 'AB')
Try this:
SELECT DISTINCT A.CustomerId From Attributes A Where
0 = CASE
WHEN A.Class = 1 and A.Code = 'AB' THEN 1
ELSE 0
END
Edit: of course this still gives you cust 1 (doh!), you should probably use pjotrs NOT EXISTS query ideally, serves me right for not looking at the data closely enough :)