I can't make a request.
I have 3 tables.
I would like to have the following result:
services
id
name
1
service1
2
service2
settings
id
name
default_value
1
setting1
10
2
setting2
false
services_settings
id
service_id
setting_id
value
1
1
1
50
result
service_id
final_value
1
50
2
10
My query :
select
services.id,
coalesce(services_settings.value, settings.default_value)
from services
left join services_settings on services_settings.service_id = services.id
left join settings on settings.id = services_settings.setting_id and settings.name = 'setting1'
Thank you
You should use CROSS JOIN here
select
services.id,
coalesce(services_settings.value, settings.default_value)
from services
left join services_settings on services_settings.service_id = services.id
cross join settings
where settings.name = 'setting1'
SQL online editor
JOIN clause and WHERE clause does the same things but logicaly differs: JOIN clause uses for jointing tables but WHERE clause uses for filtering records.
So the condition settings.name = 'setting1' need to turn into into WHERE clause for claricity. Also you can comment out WHERE clause for troubleshooting.
select
services.id,
coalesce(services_settings.value, settings.default_value)
from services
left join services_settings on services_settings.service_id = services.id
left join settings on settings.id = services_settings.setting_id
WHERE settings.name = 'setting1'
Related
I am running the following query while trying to join 3 tables :
select
a.project_id, a.acc_name, a.project_name, a.iot,a.acc_id, a.active,
b.app_fte, b.contact_person, c.cost_call_date
from
Account a, Application b, account_version c
where
a.acc_id in (Select acc_id from account where acc_name='GGG') and
EXTRACT(MONTH FROM c.cost_call_date) = 3;
Sample data from the tables are as follows :
Account :
acc_id acc_name iot acc_contact project_id project_name ilc_code license_no active
2 GGG NA YYY 7777 HHH TTR 766 false
Application :
app_id app_name app_fte contact_person acc_id
1 sfsf 4 sdsdff 2
Account_version :
line_id acc_id version_no chargable_fte cost_call_date is_approved
9 2 7 4 2018-03-20
Here acc_id is the primary key for the Account table and the foreign key for the Application and Account_version tables. When I am running the above query I am getting 30 rows I have also tried using the distinct keyword but still I get 10 rows. Please help me in getting unique rows.
Try something like this
SELECT DISTINCT a.project_id, a.acc_name, a.project_name, a.iot,a.acc_id, a.active, b.app_fte, b.contact_person, c.cost_call_date
FROM Account a
INNER JOIN Application b
USING (acc_id)
INNER JOIN account_version c
USING (acc_id)
WHERE a.acc_name = 'GGG'
AND EXTRACT(MONTH FROM c.cost_call_date) = 3
For reference as to why your query was giving you more rows than expected, try running this:
SELECT a.*, b.*
FROM generate_series(1, 10) a, generate_series(1, 10) b
What you are doing by selecting from multiple tables as you did is a cross join. What you should actually be doing is an inner join to get the rows you want, and a DISTINCT if required to get only distinct rows from the results.
select id, wk0_count
from teams
left join
(select team_id, count(team_id) as wk0_count
from (
select created_at, team_id, trunc(EXTRACT(EPOCH FROM age(CURRENT_TIMESTAMP,created_at)) / 604800) as wk_offset
from loan_files
where loan_type <> 2
order by created_at DESC) as t1
where wk_offset = 0
group by team_id) as t_wk0
on teams.id = t_wk0.team_id
I've created the query above that shows me how many loans each team did in a given week. Week 0 is the past seven days.
Ideally I want a table that shows how many loans each team did in the last 8 weeks, grouped by week. The output would look like:
Any ideas on the best way to do this?
select
t.id,
count(week = 0 or null) as wk0,
count(week = 1 or null) as wk1,
count(week = 2 or null) as wk2,
count(week = 3 or null) as wk3
from
teams t
left join
loan_files lf on lf.team_id = t.id and loan_type <> 2
cross join lateral
(select (current_date - created_at::date) / 7 as week) w
group by 1
In 9.4+ versions use the aggregate filter syntax:
count(*) filter (where week = 0) as wk0,
lateral is from 9.3. In a previous version move the week expression to the filter condition.
How about the following query?
SELECT team_id AS id, count(team_id) AS wk0_count
FROM teams LEFT JOIN loan_files ON teams.id = team_id
WHERE loan_type <> 2
AND trunc(EXTRACT(epoch FROM age(CURRENT_TIMESTAMP, created_at)) / 604800) = 0
GROUP BY team_id
Notable changes are:
ORDER BY clause in subquery was pointless;
created_at in innermost subquery was never used;
wk_offset test is moved on the WHERE clause and not done in two distinct steps;
outermost subquery was not needed.
I have a difficulty dealing with a SQL query. I use PostgreSQL.
The query says: Show the customers that have done at least an order that contains products from 3 different categories. The result will be 2 columns, CustomerID, and the amount of orders. I have written this code but I don't think it's correct.
select SalesOrderHeader.CustomerID,
count(SalesOrderHeader.SalesOrderID) AS amount_of_orders
from SalesOrderHeader
inner join SalesOrderDetail on
(SalesOrderHeader.SalesOrderID=SalesOrderDetail.SalesOrderID)
inner join Product on
(SalesOrderDetail.ProductID=Product.ProductID)
where SalesOrderDetail.SalesOrderDetailID in
(select DISTINCT count(ProductCategoryID)
from Product
group by ProductCategoryID
having count(DISTINCT ProductCategoryID)>=3)
group by SalesOrderHeader.CustomerID;
Here are the database tables needed for the query:
where SalesOrderDetail.SalesOrderDetailID in
(select DISTINCT count(ProductCategoryID)
Is never going to give you a result as an ID (SalesOrderDetailID) will never logically match a COUNT (count(ProductCategoryID)).
This should get you the output I think you want.
SELECT soh.CustomerID, COUNT(soh.SalesOrderID) AS amount_of_orders
FROM SalesOrderHeader soh
INNER JOIN SalesOrderDetail sod ON soh.SalesOrderID = sod.SalesOrderID
INNER JOIN Product p ON sod.ProductID = p.ProductID
HAVING COUNT(DISTINCT p.ProductCategoryID) >= 3
GROUP BY soh.CustomerID
Try this :
select CustomerID,count(*) as amount_of_order from
SalesOrder join
(
select SalesOrderID,count(distinct ProductCategoryID) CategoryCount
from SalesOrderDetail JOIN Product using (ProductId)
group by 1
) CatCount using (SalesOrderId)
group by 1
having bool_or(CategoryCount>=3) -- At least on CategoryCount>=3
I need to select some settings from some joined tables, but only if Items ORDER BY EndTime DESC ItemID is among first 1000 Items.
Do do this I built the following Query that, although surely can be improved, works:
SELECT ss.ModuleCode, ss.MaxItems , w.*
FROM Subscriptions ss
JOIN Sellers s ON s.UID=ss.UID
JOIN Items i ON s.UserID=i.UserID
JOIN Items ii ON i.ItemID=ii.ItemID
JOIN Modules mo ON ss.ModuleCode=mo.ModuleCode
JOIN Settings w ON w.UID=s.UID AND ss.ModuleCode=w.WCode
FULL JOIN GoogleFonts f ON f.FontCode=a.FontFamily
JOIN ( SELECT
ItemID
FROM Items
WHERE UserID=#UserID
ORDER BY EndTime DESC
OFFSET 0 ROWS
FETCH FIRST (1000) ROWS ONLY
) it ON it.ItemID=i.ItemID
WHERE it.ItemID=#ItemID
AND .....
but since MaxItems is not always 1000 and its value is defined by ss.MaxItems,
I would replace the fixed value of 1000 with the dynamic value of ss.MaxItems, but I haven't find a way to do it:
Although not optimal since makes the query much heavier, I tried putting instead of 1000 a further query with this result:
SELECT ss.ModuleCode, ss.MaxItems , w.*
FROM Subscriptions ss
JOIN Sellers s ON s.UID=ss.UID
JOIN Items i ON s.UserID=i.UserID
JOIN Items ii ON i.ItemID=ii.ItemID
JOIN Modules mo ON ss.ModuleCode=mo.ModuleCode
JOIN Settings w ON w.UID=s.UID AND ss.ModuleCode=w.WCode
FULL JOIN GoogleFonts f ON f.FontCode=a.FontFamily
JOIN ( SELECT
ItemID
FROM Items
WHERE UserID=#UserID
ORDER BY EndTime DESC
OFFSET 0 ROWS
FETCH FIRST ( SELECT ss.MaxItems
FROM Subscriptions ss
JOIN Sellers s ON s.UID=ss.UID
JOIN Items i ON s.UserID=i.UserID
JOIN Modules mo ON ss.ModuleCode=mo.ModuleCode
JOIN Settings w ON w.UID=s.UID AND ss.ModuleCode=w.WCode
WHERE i.ItemID=#ItemID) ROWS ONLY
) it ON it.ItemID=i.ItemID
Where it.ItemID=#ItemID
AND .....
but since this returns more than 1 value it is not accepted: limiting to TOP 1 result the latest subquery will work but will not be fully dynamic as required.
Can suggest how to solve or at least suggest the path for the solution?
Thanks!
Instead of fetch use row_number:
JOIN (SELECT ItemID, ROW_NUMBER() OVER (PARTITION BY UserID ORDER BY EndTime) as seqnum
FROM Items it
WHERE UserID = #UserID
) it
ON it.ItemID = i.ItemID AND seqnum <= ss.maxitems
I have the following TSQL query:
SELECT DISTINCT MyTable1.Date
FROM MyTable1
INNER JOIN MyTable2
ON MyTable1.Id = MyTable2.Id
WHERE Name = 'John' ORDER BY MyTable1.Date DESC
It retrieves a long list of Dates, but I only need the first one, the one in the first row.
How can I get it?
Thanks a ton!
In SQL Server you can use TOP:
SELECT TOP 1 MyTable1.Date
FROM MyTable1
INNER JOIN MyTable2
ON MyTable1.Id = MyTable2.Id
WHERE Name = 'John'
ORDER BY MyTable1.Date DESC
If you need to use DISTINCT, then you can use:
SELECT TOP 1 x.Date
FROM
(
SELECT DISTINCT MyTable1.Date
FROM MyTable1
INNER JOIN MyTable2
ON MyTable1.Id = MyTable2.Id
WHERE Name = 'John'
) x
ORDER BY x.Date DESC
Or even:
SELECT MAX(MyTable1.Date)
FROM MyTable1
INNER JOIN MyTable2
ON MyTable1.Id = MyTable2.Id
WHERE Name = 'John'
--ORDER BY MyTable1.Date DESC
There are several options here. You can use TOP(1) as Taryn mentioned. But according to docs for the purposes of limiting the rows returned it is better to use OFFSET and FETCH.
We recommend that you use the OFFSET and FETCH clauses instead of the TOP clause to implement a query paging solution and limit the number of rows sent to a client application.
Using OFFSET and FETCH as a paging solution requires running the query one time for each "page" of data returned to the client application. For example, to return the results of a query in 10-row increments, you must execute the query one time to return rows 1 to 10 and then run the query again to return rows 11 to 20 and so on.
Assuming, the solution for your problem using OFFSET and FETCH approach could be:
SELECT DISTINCT MyTable1.Date
FROM MyTable1
INNER JOIN MyTable2
ON MyTable1.Id = MyTable2.Id
WHERE Name = 'John' ORDER BY MyTable1.Date DESC
OFFSET 0 ROWS
FETCH NEXT 1 ROW ONLY