I am trying to select which co-ordinates from OA table are NOT found in the CUSTOMER address table.
SELECT DISTINCT
OA.CO_ORDS
FROM
CUSTOMER
INNER JOIN
OA ON customer.address=oa.co_ords
ORDER BY ID ASC;
Returns the co-ordinates which ARE in the customer table. How do I return those that are not in the customer table?
Am I also able to COUNT how many of customers are is in each co-ordinate (The co-ords are not specific and not accurate, this is purely for query testing only)
SELECT DISTINCT
OA.CO_ORDS
FROM
CUSTOMER
INNER JOIN
OA ON customer.address=oa.co_ords
ORDER BY ID ASC;
We can use NOT EXISTS to find those co-ordinates which don't appear in the customer table:
SELECT co_ords
FROM oa
WHERE
NOT EXISTS
(SELECT 1 FROM customers
WHERE address = oa.co_ords)
ORDER BY id;
In order to count how many customers belong to a certain co-ordinate, we can use COUNT with GROUP BY, something like this:
SELECT c.address, COUNT(*)
FROM customers c
JOIN oa
ON c.address = oa.co_ords
GROUP BY c.address;
It could be better to count a specific column instead of *.
It could also be better to use an IN clause instead of JOIN the tables:
SELECT c.address, COUNT(*)
FROM customers c
WHERE address IN
(SELECT co_ords FROM oa)
GROUP BY c.address;
Such details depend on your exact table structure, you should please try this out or provide more details.
You could also do:
SELECT co_ords
FROM oa
MINUS
SELECT address
FROM customers;
which can sometimes be faster than doing an anti-join. Note that MINUS does a distinct on the resultset.
Related
I have a table here in which I want to write a SELECT query in SQL Server that allows me to get the following:
For each unique combination of SalesPerson x Country, get only the rows with the latest Upload_DateTime
However, I am trying to do a group-by and inner join, but to no avail. My code is something like this:
SELECT t1.[SalesPerson], t1.[Country], MAX(t1.[Upload_DateTime]) as [Upload_DateTime]
FROM [dbo].[CommentTable] AS t1
GROUP BY t1.[SalesPerson], t1.[Country]
INNER JOIN SELECT * FROM [dbo].[CommentTable] as t2 ON t1.[SalesPerson] = t2.[SalesPerson], t1.[Country] = t2.[Country]
It seems like the GROUP BY needs to be done outside of the INNER JOIN? How does that work? I get an error when I run the query and it seems my SQL is not right.
Basically, this subquery will fetch the person, the country and the latest date:
SELECT
SalesPerson, Country, MAX(uplodaed_datetime)
FROM CommentTable
GROUP BY SalesPerson, Country;
This can be used on a lot of ways (for example with JOIN or with an IN clause).
The main query will add the remaing columns to the result.
Since you tried a JOIN, here the JOIN option:
SELECT
c.id, c.SalesPerson, c.Country,
c.Comment, c.uplodaed_datetime
FROM
CommentTable AS c
INNER JOIN
(SELECT
SalesPerson, Country,
MAX(uplodaed_datetime) AS uplodaed_datetime
FROM CommentTable
GROUP BY SalesPerson, Country) AS sub
ON c.SalesPerson = sub.SalesPerson
AND c.Country = sub.Country
AND c.uplodaed_datetime = sub.uplodaed_datetime
ORDER BY c.id;
Try out: db<>fiddle
I am struggling with taking a Count() from one table and dividing it by a correlating number from a different table in Microsoft SQL Server.
Here is a fictional example of what I'm trying to do
Lets say I have a table of orders. One column in there is states.
I have a second table that has a column for states, and second column for each states population.
I'd like to find the order per population for each sate, but I have struggled to get my query right.
Here is what I have so far:
SELECT Orders.State, Count(*)/
(SELECT StatePopulations.Population FROM Orders INNER JOIN StatePopulations
on Orders.State = StatePopulations.State
WHERE Orders.state = StatePopulations.State )
FROM Orders INNER JOIN StatePopulations
ON Orders.state = StatePopulations.State
GROUP BY Orders.state
So far I'm contending with an error that says my sub query is returning multiple results for each state, but I'm newer to SQL and don't know how to overcome it.
If you really want a correlated sub-query, then this should do it...
(You don't need to join both table in either the inner or outer query, the correlation in the inner query's where clause does the 'join'.)
SELECT
Orders.state,
COUNT(*) / (SELECT population FROM StatePopulation WHERE state = Orders.state)
FROM
Orders
GROUP BY
Orders.state
Personally, I'd just join them and use MAX()...
SELECT
Orders.state,
COUNT(*) / MAX(StatePopulation.population)
FROM
Orders
INNER JOIN
StatePopulation
StatePopulation.state = Orders.state
GROUP BY
Orders.state
Or aggregate your orders before you join...
SELECT
Orders.state,
Orders.order_count / StatePopulation.population
FROM
(
SELECT
Orders.state,
COUNT(*) AS order_count
FROM
Orders
GROUP BY
Orders.state
)
Orders
INNER JOIN
StatePopulation
StatePopulation.state = Orders.state
(Please forgive typos and smelling pistakes, I'm doing this on a phone.)
I need to write SQL query like:
Show all countries with more than 1000 users, sorted by user count.
The country with the most users should be at the top.
I have tables:
● Table users (id, email, citizenship_country_id)
● Table countries (id, name, iso)
Users with columns: id, email, citizenship_country_id
Countries with columns: id, name, iso
SELECT countries.name,
Count(users.citiizenship_country_id) AS W1
FROM countries
LEFT JOIN users ON countries.id = users.citizenship_country_id
GROUP BY users.citiizenship_country_id, countries.name
HAVING ((([users].[citiizenship_country_id])>2));
But this does not work - I get an empty result set.
Could you please tell me what I'm doing wrong?
A LEFT JOIN is superfluous for this purpose. To have 1000 users, you need at least one match:
SELECT c.name, Count(*) AS W1
FROM countries c JOIN
users u
ON c.id = u.citizenship_country_id
GROUP BY c.name
HAVING COUNT(*) > 1000;
Notice that table aliases also make the query easier to write and to read.
Group by country name and use HAVING Count(u.citiizenship_country_id)>1000, it filters rows after aggregation:
SELECT c.name,
Count(u.citiizenship_country_id) AS W1
FROM countries c
INNER JOIN users u ON c.id = u.citizenship_country_id
GROUP BY c.name
HAVING Count(u.citiizenship_country_id)>1000
ORDER BY W1 desc --Order top counts first
;
As #GordonLinoff pointed, you can use INNER JOIN instead of LEFT JOIN, because anyway this query does not return counries without users and INNER JOIN performs better because no need to pass not joined records to the aggregation.
I needed to print ( show ) the max of the table created by the following code:
SELECT name, SUM(cost)+SUM(DISTINCT stock*cost) AS result
FROM publishers
NATURAL JOIN editions
NATURAL JOIN shipments
NATURAL JOIN stock
GROUP BY name
I have tried using DESC but am not allowed to use it
SELECT MAX(result) from (SELECT name, SUM(cost)+SUM(DISTINCT stock*cost) AS result FROM publishers NATURAL JOIN editions NATURAL JOIN shipments NATURAL JOIN stock group by name )
This nested query should do if you only need max of result.
I have an orders table that stores orders from multiple sites within our company. In the table we have the fields userid, ordernumber and sitename. What I'd like to be able to get is the number of users who have orded from 2 or more of our sites.
This is what I started with:
SELECT
o.ordernumber,
o.sitename,
o.userdbid,
o2.sitename,
o2.userdbid,
o2.ordernumber
FROM
orders o
INNER JOIN
orders o2
ON
o.userdbid = o2.userdbid
WHERE
o.sitename != o2.sitename
ORDER BY
o.userdbid;
This isn't close to correct but this as close as I could think to get. Any help or direction would be very much appreciated.
You will need a HAVING clause to compare the aggregate COUNT() to 2, wherein you have grouped by userbid. Be sure to use DISTINCT in your aggregate COUNT() so that you get multiple sites rather than just multiple orders.
SELECT
o.userbid,
COUNT(DISTINCT o.sitename) AS num_order_sites
FROM
orders o
GROUP BY o.userbid
HAVING COUNT(DISTINCT o.sitename) >= 2
If you're looking just for users who have ordered from more than one site you don't actually need to do a self join. You just need this.
SELECT
o.userdbid
FROM
orders o
GROUP BY o.userdbid
HAVING
COUNT(o.sitename) > 1
If you want to then find additional information you can join back to these results.
e.g.
SELECT
o.ordernumber,
o.sitename,
o.userdbid
FROM orders o
INNER JOIN (SELECT o.userdbid
FROM orders o
GROUP BY o.userdbid
HAVING Count( DISTINCT o.sitename) > 1) morethanOne
ON o.userdbid = morethanone.o.userdbid
UPDATE: Plese note Michael's point about DISTINCT
DEMO