My problem is very specific and I couldn't figure out a better name for the title.
I have 3 tables, which are Pessoa (Person), Bicicleta (Bicicle) and Viagem (Trip):
What I want to do is select the names of the individuals by alphabetic order who had a trip, together with the Avaliacao (Evaluation) multiplied by Valor_Viagem (Trip cost).
What I tried to do (not working properly nor finished):
select distinct PESSOA.Nome, VIAGEM.Avaliacao, VIAGEM.Id_Bicicleta, BICICLETA.Valor_Viagem from PESSOA, VIAGEM
join BICICLETA ON VIAGEM.Id_Bicicleta = BICICLETA.Id where PESSOA.Email IN (
SELECT Email_Utilizador FROM VIAGEM
);
Which gives me:
^This is NOT what I want, as stated before.
I am also not 100% sure what you are looking for, but I assume you need a list of distinct names that contains the Avalacao * Valor_Viagem summed for each person (so a person with 5 trips has five times Avalacao * Valor_Viagem + ... + ...).
That is very easy to achieve:
select PESSOA.Nome, VIAGEM.Avaliacao, VIAGEM.Id_Bicicleta, BICICLETA.Valor_Viagem from PESSOA, VIAGEM, SUM(VIAGEM.Avaliacao * BICICLETA.Valor_viagem) AS trip_cost
join BICICLETA ON VIAGEM.Id_Bicicleta = BICICLETA.Id where PESSOA.Email IN (
SELECT Email_Utilizador FROM VIAGEM
) GROUP BY PESSOA.Nome;
What happens is the following:
first you compute the product for each trip
than you use the GROUP BY clause to group persons with identical names together
using SUM in combination with GROUP BY causes to sum all values of persons within this group, in that case all records with the same PESSOA.Nome
A word of warning
This assumes you will have distinct names. This appears risky. Better assign each person a unique Id and use this Id as foreign key instead of the name.
Related
the title doesnt describe it that well, my problem:
I have 2 tables, one table for orders, the other for the product.
An order can have n products associated with it.
I want to select those orders, where all their associated products have a status (attribute of the product) greater or equal to x. (So I know that every product of my order is "ready" and the order can be processed further)
Every ordered product has an OrderID
Any tips?
e: Just started with SQL, dont bash me if this is a stupid question
It's a matter of mindset.
You have to find the 'dual' form of your question ( -> double negation).
You need to find all the orders that have AT LEAST one line that is not ready.
Assuming your tables are the common:
Order(ID,bla,bla,bla) and Order Line(orderID, row#, status, bla, bla) FK orderid references order.
You can use this stub:
Select *
from orders O
where not exists ( select * from order_line OL
where ol.orderID=O.orderID --binding with outer query
and status <> 'ready'
)
SIDE NOTE: my query will produce also empty orders, to filter them just add to outer query and exists (select * from orderline oe where oe.orderid=o.orderid)
I am trying to retrieve the the first row among the duplicate row, THE FIRST OCCURED ***
--Table--
Order_No Product User
1 Book Student
2 Book Student
3 Book Student
I want to get the Order_No of the first duplicate row in JAVA, I have used DISTINCT and DISTINCT TOP 1 etc but nothing worked, NEED HELP
SELECT min(order_no), product, user
FROM 'table'
GROUP BY user, product
This is basic SQL?
SELECT min(order_no), product, user FROM table GROUP BY product, user
See also more information on GROUP BY
All fields not part of your group by must have some sort of way to determine which to pick of the n potentially different values. min() will pick the lowest value (even with strings and dates) while max() will pick the highest. You can also use First() and Last() to grab the value according to when they show up.
Supposing you had other values to pick from, you might see something like:
SELECT min(order_no), product, user, min(creation_date),
sum(quantity), first(billing_address)
FROM orders GROUP BY product, user
SELECT t.*
FROM table t
WHERE NOT EXISTS ( SELECT a
FROM table t2
WHERE t2.Product = t.Product
AND t2.User = t.User
AND t2.Order_No < t.Order_No
)
So, let's say I have a hash/relational table that connects users, teams a user can join, and challenges in which teams participate (teams_users_challenges), as well as a table that stores entered data for all users in a given challenge (entry_data). I want to get the average scores for each user in the challenge (the average value per day in a given week). However, there is a chance that a user will somehow join more than one team erroneously (which shouldn't happen, but does on occasion). Here is the SQL query below that gets a particular user's score:
SELECT tuc.user_id, SUM(ed.data_value) / 7 as value
FROM teams_users_challenges tuc
LEFT JOIN entry_data ed ON (
tuc.user_id = ed.user_id AND
ed.entry_date BETWEEN '2013-09-16' AND '2013-09-22'
)
WHERE tuc.challenge_id = ___
AND tuc.user_id = ___
If a user has mistakenly joined more than one team, (s)he would have more than one entry in teams_users_challenges, which would essentially duplicate the data retrieved. So if a user is on 3 different teams for the same challenge, (s)he would have 3 entries in teams_users_challenges, which would multiply their average value by 3, thanks to the LEFT JOIN that automatically takes in all records, and not just one.
I've tried using GROUP BY, but that doesn't seem to restrict the data to only one instances within teams_users_challenges. Does anybody have any ideas as to how I could restrict the query to only take in one record within teams_users_challenges?
ADDENDUM: The columns within teams_users_challenges are team_id, user_id, and challenge_id.
If this is a new empty table, you can express your 'business rule' that a user should only join one team per challenge as a unique constraint in SQL:
alter table teams_users_challenges
add constraint oneUserPerTeamPerChallenge
unique (
user_id
, team_id
, challenge_id
);
If you can't change the table, you'll need to group by user and team and pick a single challenge from each group in the query result. Maybe pick just the latest challenge.
I can't test it, but if you can't clean up the data as Yawar suggested, try:
SELECT tuc.user_id, SUM(ed.data_value) / 7 as value
FROM entry_data ed
LEFT JOIN
(
select tuc.user_id, tuc.challenge_id from teams_users_challenges tuc group by tuc.user_id, tuc.challenge_id
) AS SINGLE_TEAM
ON SINGLE_TEAM.user_id = ed.user_id AND
ed.entry_date BETWEEN '2013-09-16' AND '2013-09-22'
WHERE tuc.challenge_id = ___
AND tuc.user_id = ___
I have a table Mbr that contains 3 fields, GroupType, LeaderID, and MemberID. Basically, all the members in an organization are divided up into these groups, identified by their leader's unique ID (LeaderID). Each member record also has their own MemberID, and the leaders themselves have a unique MemberID as well. The GroupType just designates whether the group a member is in which is considered a Large, Small, or Individual group.
I need to find out how many groups of each GroupType contain a certain number of members.
For example:
How many Large groups contain 6 members, 7 members, 8 members, 9 and so on.
How many Small Groups contain 2 members, 3 members, 4 members and 5 members
How many Individual groups there are.
Is it possible make a query to get a Count of the unique MemberID's for each group, and then get a COUNT of how many LeaderID's have a certain number of members associated to them?
Note: Since you are not specifying which DBMS you are using, I tried to do a basic query. In SQLServer or Oracle this can be much more elegant.
I'm assuming that a given Member can be Leader leader of only one Group if that is correct,
Question #1:
SELECT GroupType, NumberOfMembers, COUNT(LeaderID) AS NumberOfGroups
FROM (
SELECT GroupType, LeaderID, COUNT(*) AS NumberOfMembers
FROM MyTable
GROUP BY GroupType, LeaderID
) AS InnerGrouping
GROUP BY GroupType, NumberOfMembers
ORDER BY GroupType, NumberOfMembers
Question #2:
SELECT UniqueMemberIDPerGroup, COUNT(LeaderID) AS NumberOfLeaderID
FROM (
SELECT LeaderID, COUNT(DISTINCT MemberID) AS UniqueMemberIDPerGroup
FROM MyTable
GROUP BY LeaderID
) AS InnerGrouping
GROUP BY UniqueMemberIDPerGroup
I'm sure you can write some complex query with several subqueries to create a query to give you what you want, but I personally like more straightforward methods. In this case, it would be using some temp tables to store intermediate values. I would first group by several columns (that you are going to use as criterias) with count being the value for the query. I would then store these into a temp table and finally create a query to utilize the temp table to give you the results that you are looking for.
I have 2 tables:
matches TABLE
FIELDS: record, date, competition
outrights TABLE
FIELDS: record, competition
What I would like, is to select rows grouped by the different types of competition. Below are the statements that work fine when I treat each table seperately.
Firstly, from 'matches' and only if the date hasn't already past:
SELECT competition, date FROM matches WHERE date >= '$currentTime' GROUP BY competition
Followed by rows from 'outrights':
SELECT competition FROM outrights GROUP BY competition
This is all pretty straight forward, except the same competition values will often (but not always) appear in both tables. I have looked at many different methods (including LEFT and RIGHT JOINS), but haven't found a simple solution. Basically I want the different competition types that appear in both tables, without duplication. Is this possible?
Is this what you are looking for. A little confused by the question but it appears that you want a DISTINCT listing of the competition column from both tables
SELECT DISTINCT competition
FROM
(
SELECT competition FROM matches
UNION
SELECT competition from outrights
) AS t
If you need the distinct competitions that appear only in both tables and not just one or both you could use
SELECT DISTINCT competition
FROM
(
SELECT competition FROM matches INNER JOIN
outrights ON matches.competition = outrights.competition
) AS t