I need to join table_1 and table_2 in MySQL and compare which user has the most winnings. Then update table_2.winner with the user id which has won..
table 1
city user winnings
1 a 99
1 b 0
1 c 50
1 d 2
table 2
city user_1 user_2 winner
1 a b a
1 c d 50
However I'm struggling to figure out how to join the tables thus far I have
SELECT table_1.winnings AS win_a, table_1.winnings AS win_b
FROM table_1, table_2
WHERE table_2.user_1 = table_1.user
AND table_2.user_2 = table_1.user
http://sqlfiddle.com/#!2/c855b/1
You can join against the table multiple times like this:
SELECT IF(user1.winnings > user2.winnings, "user1", "user2")
FROM table_2 games
JOIN table_1 user1 ON games.user_1 = user1.user
JOIN table_1 user2 ON games.user_2 = user2.user
http://sqlfiddle.com/#!2/c855b/16
I just used #skishore's query, a bit fixed, because it is broken for draws. The one that takes draws under consideration would be
SELECT
case when user1.winnings > user2.winnings then user1.user
when user2.winnings > user1.winnings then user2.user
else null
end
FROM table_2 games
JOIN table_1 user1 ON games.user_1 = user1.user
JOIN table_1 user2 ON games.user_2 = user2.user
But apart from this, I still don't get the purpose. I wrote this in comment to #skishore answer, but paste it here also. Consider the case:
User c won 99 matches played with user b, user d on the other hand won 2 matches played with user c. But who will be the winner between c and d? C
The second question is - why do you need this stored in a separate table? Winnings number will be dynamically changing so you would have to create trigger to keep winner column on table2 up to date. Can't you just get winner using this query?
Related
I have TableA with 5 rows in column siteID ( so 5 different sites).
I have TableB that stores userIDs and which sites they have access to. I need to take all 5 siteIDs from TableA and check to see if any of the siteIDs are NOT in TableB for a specific user.
I'm trying something similar to this pseudocode but not sure how the syntax should go:
SET #invalidSites = (
SELECT COUNT(*)
FROM userSiteAccess AS usa
RIGHT JOIN customer.sitesVsUsers AS cust
ON usa.listOfSites = cust.siteID
WHERE cust.siteID IS NULL);
EXAMPLE:
TABLE A
listOfSites
1
2
3
TableB
userID siteAccess
50 3
The count should return 2 as the list of sites has 2 additional rows (site 1 and site 2) but the user only has access to site 3.
You need to use LEFT JOIN rather than RIGHT JOIN, and you need to specify the user ID in the ON condition.
SELECT COUNT(*)
FROM userSiteAccess AS usa
LEFT JOIN sitesVsUsers AS cust
ON usa.listOfSites = cust.siteID AND cust.userId = 2
WHERE cust.siteID IS NULL
DEMO
With NOT EXISTS:
select count(*) counter
from tablea a
where not exists (
select 1 from tableb
where userid = 50 and siteaccess = a.listofsites
)
Does anyone know the solution to this problem ?
There are 3 Tables: orders, order_groups and stores.
I want to list the orders, with the names of the stores where the order was placed, and where the order is going to be delivered.
I keep the from_store_id, and to_store_id in the order_groups table
Listing these orders would be simple, i just left join the order_groups to orders, and select the name, from_shop_id and to_shop_id, but the problem is i want the name of the stores not the id, and the store names are placed in a different table (stores)
Here is what im talking about:
Table orders
id group_id name madeup_id
1 11 johnny cash 1
2 12 billy bob 1
LEFT JOIN order_groups on order_groups.id = orders.group_id
Table order_groups
id from_store_id to_store_id
11 55 56
12 56 55
Table stores
id store_name
55 thisstore
56 thatstore
The result im looking for is:
name from_store to_store
1.johhny cash thisstore, thatstore
2.billy bob thatstore, thisstore
The statement i have yet:
SELECT
orders.name, something as from_store, something as to_store
FROM orders
LEFT JOIN order_groups on order_groups.id = orders.group_id
somehow join stores on the order_groups.from_store_id = stores.id
WHERE orders.madeup_id = 1
Any idea how to select and join the store names to the query ?
One more question. I actually want to list two kind of orders in one query from different tables too, im on the right track with this structure ?
SELECT a,b FROM a LEFT JOIN b ON b.something=a.something WHERE something
UNION ALL
SELECT a,b FROM c LEFT JOIN c ON c.something=a.something WHERE something
You only need to join 2 times the same table!
SELECT
orders.name, fromStore.store_name as from_store, toStore.store_name as to_store
FROM orders
LEFT JOIN order_groups on order_groups.id = orders.group_id
left join stores fromStore on the order_groups.from_store_id = fromStore.id
left join stores toStore on the order_groups.to_store_id = toStore.id
WHERE orders.madeup_id = 1
I have a user table:
id, userID, name, postcode
2 99 Bob AAA BBB
3 8384 Jim CCC DDD
And I have a user-keys table:
id, userID, keyID, val
1 435 3 1
2 773 8 0
3 99 2 1
4 99 5 1
5 99 2 1
Where keyID = 2 indicates that it is a staff member. I want to get all the userIDs from user table that are not staff members. So far I have the following SQL:
SELECT u.`userID` FROM `users` u
WHERE u.`userID` IS NOT NULL AND u.`userID` != 0;
However this does not exclude all users that have an entry in user-keys table with a keyID value of 2 and val of 1.
How can I perform this?
Edit: I neglected to state that any user may have multiple entries in the user-keys table, and I just want one list of userID from the user table, So really the results I am looking for from the above tables would simply be 8384.
You can try the following join query:
SELECT
t1.userID
FROM user t1
LEFT JOIN
(
SELECT DISTINCT userID, keyID -- you don't need DISTINCT here, but it may help
FROM `user-keys` -- and it makes the logic a bit clearer
WHERE keyID = 2
) t2
ON t1.userID = t2.userID
WHERE t2.userID IS NULL
The logic used here is that we retain all users from the user table who do not appear in user-keys with a keyID of 2, or who do not appear in user-keys at all.
Follow the link below for a demo in MySQL. Note that in some databases user-keys would not be a valid table name and would need to be escaped (I escaped above using backticks, SQL Server would use [user-keys], etc.).
Rextester
Update:
If you want to find only staff members, then the logic is much simpler. In this case, we can just INNER JOIN the two tables together and check the status of each user:
SELECT DISTINCT
t1.userID
FROM user t1
INNER JOIN `user-keys` t2
ON t1.userID = t2.userID
WHERE t2.keyID = 2
If you want the user with keyID <> 2 you should use a inner join
SELECT u.userID
FROM users u
and u.userID not in (select userID
from `user-keys`
WHERE keyID <>2 )
You can use below code
SELECT * FROM USER WHERE ID IN
(SELECT ID FROM USER_KEY WHERE KEY_ID <> 2);
If you need all columns you can use,
SELECT * FROM USER U
INNER JOIN USER_KEY UK
ON(U.ID = UK.ID)
WHERE UK.KEYID <> 2;
I have the following tables:
Users
user_id course_id completion_rate
1 2 0.4
1 23 0.6
1 49 0.5
... ... ...
Courses
course_id title
1 Intro to Python
2 Intro to R
... ...
70 Intro to Flask
Each entry in the user table represents a course that the user took. However, it is rare that users have taken every course.
What I need is a result set with user_id, course_id, completion_rate. In the case that the user has taken the course, the existing completion_rate should be used, but if not then the completion_rate should be set to 0. That is, there would be 70 rows for each user_id, one for each course.
I don't have a lot of experience with SQL, and I'm not sure where to start. Would it be easier to do this in something like R?
Thank you.
You should first cross join the courses with distinct users. Then left join on this to get the desired result. If the user hasn't taken a course the completion_rate would be null and we use coalesce to default a 0.
select c.course_id,cu.user_id,coalesce(u.completion_rate,0) as completion_rate
from courses c
cross join (select distinct user_id from users) cu
left join users u on u.course_id=c.course_id and cu.user_id=u.user_id
Step1: Take the distinct client_id from client_data (abc) and do 1 on 1 merge with the course data (abc1) . 1 on 1 merge helps up write all the courses against each client_id
Step2: Merge the above dataset with the client info on client_id as well as course
create table ans as
select p.*,case when q.completion_rate is not null then q.completion_rate else 0
end as completion_rate
from
(
select a.client_id,b.course from
(select distinct client_id from abc) a
left join
abc1 b
on 1=1
) p
left join
abc q
on p.client_id = q.client_id and p.course = q.course
order by client_id,course;
Let me know in case of any queries.
I have a table like this:
user_id | wants_user_id | state
And I want to select rows which are mutual and have a state column with value "yes" or "maybe".
Example data:
Row 1: 1 | 2 | "yes"
Row 2: 2 | 1 | "maybe"
Row 3: 3 | 2 | "yes"
In this case I would like to select row 1 and 2 and on wants_user_id (second column) I would like to join user data from table users, but I can't figure out the sql command.
Thank you for your help.
Use a self-join to get matching rows (I'm assuming "mutual rows" here means users that want each other):
SELECT *
FROM myTable a
INNER JOIN myTable b ON a.user_id = b.wants_user_id
AND b.user_id = a.wants_user_id
INNER JOIN users ua ON a.user_id = ua.id
INNER JOIN users ub ON b.user_id = ub.id
WHERE a.state IN ('yes', 'maybe')
AND b.state IN ('yes', 'maybe')
In this case, you will get two "duplicate" rows, one for 1<->2 and one for 2<->1. To eliminate this, you can add a AND b.user_id > a.user_id to the join condition - this will select only one row of each pair.