My tables are Store(ID, Name), Orders(ID, StoreID), OrderItem(ID, Quantity, OrderID, ProductID).
From the below code, i've got the Orders.ID when product 1 outsells product 2.
Now i need to refer to the store ID and get the name of the store. I'm stuck here.
When I try to add SELECT * FROM the below code, I got error ambiguous column name: OrderID.
What should I do?
SELECT OrderID as OID
FROM
(
SELECT *
FROM OrderItem as OI
WHERE OI.ProductID = 1
) AS A,
(
SELECT *
FROM OrderItem as OI
WHERE OI.ProductID = 2
) AS B
WHERE A.OrderID = B.OrderID AND A.Quantity > B.Quantity
The join you performed provides two tables A and B, both of them having the column OrderID, hence the SQL engine couldn't interpret which of the columns to display, thereby giving you the error. What you need to do is as follows:
SELECT A.OrderID as OID
FROM
(
SELECT *
FROM OrderItem as OI
WHERE OI.ProductID = 1
) AS A,
(
SELECT *
FROM OrderItem as OI
WHERE OI.ProductID = 2
) AS B
WHERE A.OrderID = B.OrderID AND A.Quantity > B.Quantity
When the column used for a join has the same name in both tables, you can use the USING clause, which not only saves typing, but also removes the duplicate column from the result:
SELECT OrderID as OID
FROM
(
SELECT *
FROM OrderItem as OI
WHERE OI.ProductID = 1
) AS A
JOIN
(
SELECT *
FROM OrderItem as OI
WHERE OI.ProductID = 2
) AS B
USING (OrderID)
WHERE A.Quantity > B.Quantity;
Related
There are two types of rows in document_files table - that have active=1 or active=0. Each document (document_id) can have multiple rows of each type. The goal is to for every document select all rows that have active=1, but only the latest one of all rows that have active=0.
select *
from documents d
inner join document_files df on df.document_id = d.id
where ...
-- df.active = 1, select them all
-- or df.active = 0, only select max(df.last_stamp) of all df.active=0 rows for this df.document_id
How to achieve this?
I'd use union and group by, but the problem is that a lot of columns are returned, and it wouldn't be optimal to group them all.
This section only get the document files with no active record and after that using max () gets the most recent record for the item:
select document_id
from (select * from document_files f where f.document_id not in
(select document_id from document_files where active = 1)) dff where dff.last_stamp =
(
select max(i.last_stamp) from document_files i where i.document_id = dff.document_id
)
My final sql :
select *
from documents d
inner join document_files df on df.document_id = d.id
where df.active = 1 or
df.document_id in
(
select document_id
from (select * from document_files f where f.document_id not in
(select document_id from document_files where active = 1)) dff where dff.last_stamp =
(
select max(i.last_stamp) from document_files i where i.document_id = dff.document_id
)
)
Please add some sql fiddle next time so we can test the result
I'm very new to learning SQL, I apologize if my question isn't completely accurate.
The question I'm trying to answer with this query is "What is the most popular music genre in each country?" I've had to use a subquery and it works, but I found that for a few countries in the table, more than one genre has the MAX value. I'm stuck with how to edit my query so that all genres with the max value show in the results. Here is my code, using DB Browser for SQLite:
SELECT BillingCountry AS Country , name AS Genre , MAX(genre_count) AS Purchases
FROM (
SELECT i.BillingCountry, g.name, COUNT(g.genreid) AS genre_count
FROM Invoice i
JOIN InvoiceLine il
ON il.InvoiceId = i.InvoiceId
JOIN TRACK t
ON il.trackid = t.TrackId
JOIN Genre g
ON t.genreid = g.GenreId
GROUP BY 1,2
) sub
GROUP BY 1
Here is an example of the result:
| Country | Genre |Purchase|
|---------|-------|--------|
|Agrentina| Punk | 9 |
|Australia| Rock | 22 |
BUT in running just the subquery to COUNT the purchases, Argentina has two Genres with 9 Purchases (the max number for that country). How do I adjust my query to include both and not just the first one in the row?
You can do it with RANK() window function:
SELECT BillingCountry, name, genre_count
FROM (
SELECT i.BillingCountry, g.name, COUNT(*) AS genre_count,
RANK() OVER (PARTITION BY i.BillingCountry ORDER BY COUNT(*) DESC) rnk
FROM Invoice i
INNER JOIN InvoiceLine il ON il.InvoiceId = i.InvoiceId
INNER JOIN TRACK t ON il.trackid = t.TrackId
INNER JOIN Genre g ON t.genreid = g.GenreId
GROUP BY i.BillingCountry, g.name
)
WHERE rnk = 1
This will return the ties in separate rows.
If you want 1 row for each country, you could also use GROUP_CONCAT():
SELECT BillingCountry, GROUP_CONCAT(name) AS name, MAX(genre_count) AS genre_count
FROM (
SELECT i.BillingCountry, g.name, COUNT(*) AS genre_count,
RANK() OVER (PARTITION BY i.BillingCountry ORDER BY COUNT(*) DESC) rnk
FROM Invoice i
INNER JOIN InvoiceLine il ON il.InvoiceId = i.InvoiceId
INNER JOIN TRACK t ON il.trackid = t.TrackId
INNER JOIN Genre g ON t.genreid = g.GenreId
GROUP BY i.BillingCountry, g.name
)
WHERE rnk = 1
GROUP BY BillingCountry
In this query, I want to use with-statement. I have a subquery that calculates A union all B and I want to use it with with-statement. But when I use with-statement I face the error that says "table or view does not exist".
what surprises me is when I replace the first part with with-statement it works correctly. But when I replace the second part, I face this error!!
select
deposit.BRNCH_COD||'-'||deposit.DP_TYPE_COD||''||deposit.CUSTOMER_NUM||'-
'||deposit.DEPOSIT_SERIAL AS DEPOSIT_NUMBER,
deposit.IBAN AS IBAN,
deposit.CURRENCY_DESC AS DEPOSIT_CURRCOD,
deposit.BRNCH_COD AS BRNCH_COD,
MAIN_7.Still_Days
AS Still_Lenght,
to_char(MAIN_7.Startdate, 'yyyy/mm/dd' ,'nls_calendar=persian') AS
START_DATE,
MAIN_7.AMOUNT
AS TOTAL_AMOUNT,
MAIN_7.TRN_Count
AS TRN_Count
from
(
select Trans_Table.DEPOSIT_KEY AS DEPOSIT_KEY,
Trans_Table.TRN_Start_DATE AS Startdate,
MAX(Active_Time_Table.EFFECTIVE_DATE) AS Lastdate,
H.PASSIVE_DAYS AS Still_Days,
SUM(Active_Time_Table.AMOUNT) AS AMOUNT,
Count(Active_Time_Table.AMOUNT) AS TRN_Count
from
(
Select F.DEPOSIT_KEY,
SUM (F.AMOUNT) AS TRN_AMOUNT,
MIN (F.EFFECTIVE_DATE) AS TRN_Start_DATE
from
(
A
union all
B
)F
Group by (F.DEPOSIT_KEY)
Having ( SUM (F.AMOUNT) >10000000000)
)Trans_Table
inner join
H
on (Trans_Table.DEPOSIT_KEY = H.DEPOSIT_KEY and
Trans_Table.TRN_Start_DATE-1 = H.EFFECTIVE_DATE)
inner join
(
A
union all
B
)Active_Time_Table
on (Trans_Table.DEPOSIT_KEY = Active_Time_Table.DEPOSIT_KEY and
Active_Time_Table.EFFECTIVE_DATE - Trans_Table.TRN_Start_DATE< 4 and
Active_Time_Table.EFFECTIVE_DATE - Trans_Table.TRN_Start_DATE>=0)
group by ( Trans_Table.DEPOSIT_KEY ,
Trans_Table.TRN_Start_DATE,H.PASSIVE_DAYS)
Having (SUM(Active_Time_Table.AMOUNT)) > 10000000000
)MAIN_7
inner join dimamldeposit deposit
on deposit.DEPOSIT_KEY = MAIN_7.DEPOSIT_KEY
***********************************************************
with rep as
(A union all B)
select
deposit.BRNCH_COD||'-'||deposit.DP_TYPE_COD||'-
'||deposit.CUSTOMER_NUM||'-'||deposit.DEPOSIT_SERIAL AS DEPOSIT_NUMBER,
deposit.IBAN AS IBAN,
deposit.CURRENCY_DESC AS DEPOSIT_CURRCOD,
deposit.BRNCH_COD AS BRNCH_COD,
MAIN_7.Still_Days AS Still_Lenght,
to_char(MAIN_7.Startdate, 'yyyy/mm/dd' ,'nls_calendar=persian') AS START_DATE,
MAIN_7.AMOUNT AS TOTAL_AMOUNT,
MAIN_7.TRN_Count AS TRN_Count
from
(
select Trans_Table.DEPOSIT_KEY AS DEPOSIT_KEY,
Trans_Table.TRN_Start_DATE AS Startdate,
MAX(rep.EFFECTIVE_DATE) AS Lastdate,
H.PASSIVE_DAYS AS Still_Days,
SUM(rep.AMOUNT) AS AMOUNT,
Count(rep.AMOUNT) AS TRN_Count
from
(
Select rep.DEPOSIT_KEY,
SUM (rep.AMOUNT) AS TRN_AMOUNT,
MIN (rep.EFFECTIVE_DATE) AS TRN_Start_DATE
from
rep
Group by (rep.DEPOSIT_KEY)
Having ( SUM (rep.AMOUNT) >10000000000)
)Trans_Table
inner join
H
on (Trans_Table.DEPOSIT_KEY = H.DEPOSIT_KEY and Trans_Table.TRN_Start_DATE-1 = H.EFFECTIVE_DATE)
inner join
rep rep
on (Trans_Table.DEPOSIT_KEY = rep.DEPOSIT_KEY and rep.EFFECTIVE_DATE - Trans_Table.TRN_Start_DATE< 4 and rep.EFFECTIVE_DATE - Trans_Table.TRN_Start_DATE>=0)
group by ( Trans_Table.DEPOSIT_KEY , Trans_Table.TRN_Start_DATE,H.PASSIVE_DAYS)
Having (SUM(rep.AMOUNT)) > 10000000000
)MAIN_7
inner join dimamldeposit deposit
on deposit.DEPOSIT_KEY = MAIN_7.DEPOSIT_KEY
That's a lot of code, but - to make it simple, I'd suggest you use WITH factoring clause as the first command, include all tables you use into it, and then - as the final SELECT - fetch data from all those CTEs. Something like this:
with
a as (select ... from ...),
b as (select ... from ...),
f as (select ... from ...),
...
select a.col1, b.col2, f.col3
from a join b on a.id = b.id
left join f on f.id = b.id
where ...
I realize i'm far off the solution with what i have:
Select FirstName || ' ' || LastName AS Manager From Employee
Where (Select COUNT(ReportsTo) from Employee
group by ReportsTo
order by ReportsTo desc);
ReportsTovalues are the EmployeeID they report to
What i want is to query the name of the employee with the most Employees reporting to them and who they in turn report to without nulls. I'm Not sure how to make the connections between columns values such as ReportsTo to EmployeeID so any explanation would help
For Example the output i would want is two columns say | Fred Jones | Mary Anne| the first being the employee with the most reportsTo with the same value as their EmployeeID and the second being the name of the employee with the same EmployeeID as the first employees ReportTo
Do this step by step:
First step: Count how many employees report to a person.
select reportsto, count(*) from employee group by reportsto;
We can order this result by count(*) and limit it to only get one row, so as to get the person with the most reporters. Only problem is: What to do in case of ties, i.e. two persons have the same highest amount of reporters? SQLite doesn't offer much to help here. We'll have to query twice:
select reportsto
from employee
group by reportsto
having count(*) =
(
select count(*)
from employee
group by reportsto
order by count(*) desc
limit 1
);
Next step: Get the name. That means we must access the table again.
select
firstname || ' ' || lastname as manager
from employee
where e1.employeeid in
(
select reportsto
from employee
group by reportsto
having count(*) =
(
select count(*)
from employee
group by reportsto
order by count(*) desc
limit 1
)
);
Last step: Get the persons our found managers themselves report to. These can be many, so we group by manager and concatenate all those they report to.
select
e1.firstname || ' ' || e1.lastname as manager,
group_concat(e2.firstname || ' ' || e2.lastname) as reportsto
from employee e1
join employee e2 on e2.employeeid = e1.reportsto
where e1.employeeid in
(
select reportsto
from employee
group by reportsto
having count(*) =
(
select count(*)
from employee
group by reportsto
order by count(*) desc
limit 1
)
)
group by e1.firstname || ' ' || e1.lastname;
SELECT e.ReportsTo AS TopManagersEmployeeId, COUNT(e.ReportsTo) AS ReportedBy, m.FirstName + ' ' + m.LastName AS TopManagersName, mm.FirstName + ' ' + mm.LastName AS TheirManagersName FROM Employees e
JOIN Employees m
ON e.ReportsTo = m.EmployeeID
JOIN Employees mm
ON m.ReportsTo = mm.EmployeeID
GROUP BY e.ReportsTo, m.FirstName, m.LastName, mm.FirstName, mm.LastName
Once you have this data, you can do TOP 1 etc. You can also play around with JOIN, and make it INNER JOIN in the second set where Manager's Manager (mm) is being retrieved.
I keep getting this error in SQLite:
Query Error: near "FROM": syntax error Unable to execute statement
SELECT Name, CourseId
FROM Lecturer JOIN Lecture ON Lecturer.LecturerId = Lecture.LecturerId
JOIN (SELECT CourseId
FROM Course
WHERE EXISTS (SELECT *
FROM Exam
WHERE Exam.CourseId = Course.CourseId
AND (SELECT COUNT *
FROM Exam
WHERE Grade > 6)
<
(SELECT COUNT *
FROM Exam
WHERE Grade < 6)))
USING Course.Id
I would normally assign the inline view an alias, e.g FOO, and join an outer table to the inline view with an on... clause:
select * from x
join
(
select someColumn, someOtherColumn...
) as FOO
on x.somecolumn = FOO.somecolumn
I would go about it this way:
select lecture.*, FOO.courseid
from lecture
join lecturer on lecture.lecturerid = lecturer.lecturerid
join
(
you inline view selecting the courses
) as FOO
on lecture.courseid = FOO.courseid
COUNT is a function, you need parens around the *
Such as:
COUNT(*)