I have a table which records users's scores at a game (a user may submit 5,10,20,as many scores as he wants).
I need to show the 20 top scores of a game, but per user. (as a user may have submitted eg 4 scores which are the top according to other users's scores)
The query i have written is:
SELECT DISTINCT
`table_highscores`.`userkey`,
max(`table_highscores`.`score`),
`table_users`.`username`,
`table_highscores`.`dateachieved`
FROM
`table_highscores`, `table_users`
WHERE
`table_highscores`.`userkey` = `table_users`.`userkey`
AND
`table_highscores`.`gamekey` = $gamekey
GROUP BY
`userkey`
ORDER BY
max(`table_highscores`.`score`) DESC,
LIMIT 0, 20;
The output result is ok, but there is a problem. When i calculate the difference of days (today-this of dateachieved) the result is wrong. (eg instead of saying "the score was submitted 22 days ago, it says 43 days ago) So,I have to do a second query for each score so to find the true date (meaning +20 queries). Is there any shorter way to find the correct date?
Thanks.
there is a problem. When i calculate the difference of days (today-this of dateachieved) the result is wrong.
There's two issues
the dateachieved isn't likely to be the value associated with the high score
you can use MySQL's DATEDIFF to return the the number of days between the current date and the dateachieved value.
Use:
SELECT u.username,
hs.userkey,
hs.score,
DATEDIFF(NOW(), hs.dateachieved)
FROM TABLE_HIGHSCORES hs
JOIN TABLE_USERNAME u ON u.userkey = hs.userkey
JOIN (SELECT ths.userkey,
ths.gamekey,
ths.max_score,
MAX(ths.date_achieved) 'max_date'
FROM TABLE_HIGHSCORES ths
JOIN (SELECT t.userkey,
t.gamekey,
MAX(t.score) 'max_score'
FROM TABLE_HIGHSCORES t
GROUP BY t.userkey, t.gamekey) ms ON ms.userkey = ths.userkey
AND ms.gamekey = ths.gamekey
AND ms.max_score = ths.score
) x ON x.userkey = hs.userkey
AND x.gamekey = hs.gamekey
AND x.max_score = hs.score
AND x.max_date = hs.dateachieved
WHERE hs.gamekey = $gamekey
ORDER BY hs.score DESC
LIMIT 20
I also changed your query to use ANSI-92 JOIN syntax, from ANSI-89 syntax. It's equivalent performance, but it's easier to read, syntax is supported on Oracle/SQL Server/Postgres/etc, and provides consistent LEFT JOIN support.
Another thing - you only need to use backticks when tables and/or column names are MySQL keywords.
In your query you should use an explicit JOIN and you don't need the DISTINCT keyword.
This query should solve your problem. I am assuming here that it is possible for a user to submit the same highscore more than once on different dates, and if that happens then you want the oldest date:
SELECT T1.userkey, T1.score, username, dateachieved FROM (
(SELECT userkey, max(score) AS score
FROM table_highscores
WHERE gamekey = $gamekey
GROUP BY userkey) AS T1
JOIN
(SELECT userkey, score, min(dateachieved) as dateachieved
FROM table_highscores
WHERE gamekey = $gamekey
GROUP BY userkey, score) AS T2
ON T1.userkey = T2.userkey AND T1.score = T2.score
) JOIN table_users ON T1.userkey = table_users.userkey
LIMIT 20
You didn't say what language you are using to calculate the difference but I'm guessing it's PHP because of the $gamekey you used there (which should be escaped properly, btw).
If your dateachieved field is in the DATETIME format, you can calculate the difference like this:
$diff = round((time() - strtotime($row['dateachieved'])) / 86400);
I think you need to clarify your question a little better. Can you provide some data and expected outputs and then I should be able to help you further?
Related
I'm learning SAP queries.
I want to get all the Measure documents from an equipement.
To do that, I use 3 tables :
EQUI, IMPTT, IMRG
The query works but I have all documents instead I only want to get the last one by Date. But I can't do that. I'm sure that I have to add a custom field, but I have tried but none of them works.
For example, my last code :
select min( IMRG~INVTS ) IMRG~RECDV
from IMRG inner join IMPTT on
IMRG~POINT = IMPTT~POINT into (INVTS, IMRGVAL)
where IMRG~POINT = IMPTT-POINT AND
IMPTT~MPOBJ = EQUI-OBJNR
and IMRG~CANCL = '' group by IMRG~MDOCM IMRG~RECDV.
ENDSELECT.
Thanks for your help.
You will need to get the date from IMRG, and the inverted timestamp field, so the MIN() of this will be the most recent - that looks correct.
However your GROUP BY looks wrong. You should be grouping on the IMPTT~POINT field so that you get one record per measurement point. Note that one Point IMPTT can have many measurements (IMRG), so something like this:
SELECT EQUI-OBJNR, IMPTT~POINT, MIN(IMRG~IMRC_INVTS)
...
GROUP BY EQUI-OBJNR, IMPTT~POINT
If I got you correctly, you are trying to get the freshest measurement of the equipment disregard of measurement point. So you can try this query, which is not so beautiful, but it just works.
SELECT objnr COUNT(*) MIN( invts )
FROM equi AS eq
JOIN imptt AS tt
ON tt~mpobj = eq~objnr
JOIN imrg AS ig
ON ig~point = tt~point
INTO (wa_objnr, count, wa_invts)
WHERE ig~cancl = ''
GROUP BY objnr.
SELECT SINGLE recdv FROM imrg JOIN imptt ON imptt~point = imrg~point INTO wa_imrgval WHERE invts = wa_invts AND imptt~mpobj = wa_objnr.
WRITE: / wa_objnr, count, wa_invts, wa_imrgval.
ENDSELECT.
I am fairly new in Access and SQL programming. I am trying to do the following:
Sum(SO_SalesOrderPaymentHistoryLineT.Amount) AS [Sum Of PaymentPerYear]
and group by year even when there is no amount in some of the years. I would like to have these years listed as well for a report with charts. I'm not certain if this is possible, but every bit of help is appreciated.
My code so far is as follows:
SELECT
Base_CustomerT.SalesRep,
SO_SalesOrderT.CustomerId,
Base_CustomerT.Customer,
SO_SalesOrderPaymentHistoryLineT.DatePaid,
Sum(SO_SalesOrderPaymentHistoryLineT.Amount) AS [Sum Of PaymentPerYear]
FROM
Base_CustomerT
INNER JOIN (
SO_SalesOrderPaymentHistoryLineT
INNER JOIN SO_SalesOrderT
ON SO_SalesOrderPaymentHistoryLineT.SalesOrderId = SO_SalesOrderT.SalesOrderId
) ON Base_CustomerT.CustomerId = SO_SalesOrderT.CustomerId
GROUP BY
Base_CustomerT.SalesRep,
SO_SalesOrderT.CustomerId,
Base_CustomerT.Customer,
SO_SalesOrderPaymentHistoryLineT.DatePaid,
SO_SalesOrderPaymentHistoryLineT.PaymentType,
Base_CustomerT.IsActive
HAVING
(((SO_SalesOrderPaymentHistoryLineT.PaymentType)=1)
AND ((Base_CustomerT.IsActive)=Yes))
ORDER BY
Base_CustomerT.SalesRep,
Base_CustomerT.Customer;
You need another table with all years listed -- you can create this on the fly or have one in the db... join from that. So if you had a table called alltheyears with a column called y that just listed the years then you could use code like this:
WITH minmax as
(
select min(year(SO_SalesOrderPaymentHistoryLineT.DatePaid) as minyear,
max(year(SO_SalesOrderPaymentHistoryLineT.DatePaid) as maxyear)
from SalesOrderPaymentHistoryLineT
), yearsused as
(
select y
from alltheyears, minmax
where alltheyears.y >= minyear and alltheyears.y <= maxyear
)
select *
from yearsused
join ( -- your query above goes here! -- ) T
ON year(T.SO_SalesOrderPaymentHistoryLineT.DatePaid) = yearsused.y
You need a data source that will provide the year numbers. You cannot manufacture them out of thin air. Supposing you had a table Interesting_year with a single column year, populated, say, with every distinct integer between 2000 and 2050, you could do something like this:
SELECT
base.SalesRep,
base.CustomerId,
base.Customer,
base.year,
Sum(NZ(data.Amount)) AS [Sum Of PaymentPerYear]
FROM
(SELECT * FROM Base_CustomerT INNER JOIN Year) AS base
LEFT JOIN
(SELECT * FROM
SO_SalesOrderT
INNER JOIN SO_SalesOrderPaymentHistoryLineT
ON (SO_SalesOrderPaymentHistoryLineT.SalesOrderId = SO_SalesOrderT.SalesOrderId)
) AS data
ON ((base.CustomerId = data.CustomerId)
AND (base.year = Year(data.DatePaid))),
WHERE
(data.PaymentType = 1)
AND (base.IsActive = Yes)
AND (base.year BETWEEN
(SELECT Min(year(DatePaid) FROM SO_SalesOrderPaymentHistoryLineT)
AND (SELECT Max(year(DatePaid) FROM SO_SalesOrderPaymentHistoryLineT))
GROUP BY
base.SalesRep,
base.CustomerId,
base.Customer,
base.year,
ORDER BY
base.SalesRep,
base.Customer;
Note the following:
The revised query first forms the Cartesian product of BaseCustomerT with Interesting_year in order to have base customer data associated with each year (this is sometimes called a CROSS JOIN, but it's the same thing as an INNER JOIN with no join predicate, which is what Access requires)
In order to have result rows for years with no payments, you must perform an outer join (in this case a LEFT JOIN). Where a (base customer, year) combination has no associated orders, the rest of the columns of the join result will be NULL.
I'm selecting the CustomerId from Base_CustomerT because you would sometimes get a NULL if you selected from SO_SalesOrderT as in the starting query
I'm using the Access Nz() function to convert NULL payment amounts to 0 (from rows corresponding to years with no payments)
I converted your HAVING clause to a WHERE clause. That's semantically equivalent in this particular case, and it will be more efficient because the WHERE filter is applied before groups are formed, and because it allows some columns to be omitted from the GROUP BY clause.
Following Hogan's example, I filter out data for years outside the overall range covered by your data. Alternatively, you could achieve the same effect without that filter condition and its subqueries by ensuring that table Intersting_year contains only the year numbers for which you want results.
Update: modified the query to a different, but logically equivalent "something like this" that I hope Access will like better. Aside from adding a bunch of parentheses, the main difference is making both the left and the right operand of the LEFT JOIN into a subquery. That's consistent with the consensus recommendation for resolving Access "ambiguous outer join" errors.
Thank you John for your help. I found a solution which works for me. It looks quiet different but I learned a lot out of it. If you are interested here is how it looks now.
SELECT DISTINCTROW
Base_Customer_RevenueYearQ.SalesRep,
Base_Customer_RevenueYearQ.CustomerId,
Base_Customer_RevenueYearQ.Customer,
Base_Customer_RevenueYearQ.RevenueYear,
CustomerPaymentPerYearQ.[Sum Of PaymentPerYear]
FROM
Base_Customer_RevenueYearQ
LEFT JOIN CustomerPaymentPerYearQ
ON (Base_Customer_RevenueYearQ.RevenueYear = CustomerPaymentPerYearQ.[RevenueYear])
AND (Base_Customer_RevenueYearQ.CustomerId = CustomerPaymentPerYearQ.CustomerId)
GROUP BY
Base_Customer_RevenueYearQ.SalesRep,
Base_Customer_RevenueYearQ.CustomerId,
Base_Customer_RevenueYearQ.Customer,
Base_Customer_RevenueYearQ.RevenueYear,
CustomerPaymentPerYearQ.[Sum Of PaymentPerYear]
;
I have created a database for an imaginary solicitors, my last query to complete is driving me insane. I need to work out the total a solicitor has made in their career with the company, I have time_spent and rate to multiply and special rate to add. (special rate is a one off charge for corporate contracts so not many cases have them). the best I could come up with is the code below. It does what I want but only displays the solicitors working on a case with a special rate applied to it.
I essentially want it to display the result of the query in a table even if the special rate is NULL.
I have ordered the table to show the highest amount first so i can use ROWNUM to only show the top 10% earners.
CREATE VIEW rich_solicitors AS
SELECT notes.time_spent * rate.rate_amnt + special_rate.s_rate_amnt AS solicitor_made,
notes.case_id
FROM notes,
rate,
solicitor_rate,
solicitor,
case,
contract,
special_rate
WHERE notes.solicitor_id = solicitor.solicitor_id
AND solicitor.solicitor_id = solicitor_rate.solicitor_id
AND solicitor_rate.rate_id = rate.rate_id
AND notes.case_id = case.case_id
AND case.contract_id = contract.contract_id
AND contract.contract_id = special_rate.contract_id
ORDER BY -solicitor_made;
Query:
SELECT *
FROM rich_solicitors
WHERE ROWNUM <= (SELECT COUNT(*)/10
FROM rich_solicitors)
I'm suspicious of your use of ROWNUM in your example query...
Oracle9i+ supports analytic functions, like ROW_NUMBER and NTILE, to make queries like your example easier. Analytics are also ANSI, so the syntax is consistent when implemented (IE: Not on MySQL or SQLite). I re-wrote your query as:
SELECT x.*
FROM (SELECT n.time_spent * r.rate_amnt + COALESCE(spr.s_rate_amnt, 0) AS solicitor_made,
n.case_id,
NTILE(10) OVER (ORDER BY solicitor_made) AS rank
FROM NOTES n
JOIN SOLICITOR s ON s.solicitor_id = n.solicitor_id
JOIN SOLICITOR_RATE sr ON sr.solicitor_id = s.solicitor_id
JOIN RATE r ON r.rate_id = sr.rate_id
JOIN CASE c ON c.case_id = n.case_id
JOIN CONTRACT cntrct ON cntrct.contract_id = c.contract_id
LEFT JOIN SPECIAL_RATE spr ON spr.contract_id = cntrct.contract_id) x
WHERE x.rank = 1
If you're new to SQL, I recommend using ANSI-92 syntax. Your example uses ANSI-89, which doesn't support OUTER JOINs and is considered deprecated. I used a LEFT OUTER JOIN against the SPECIAL_RATE table because not all jobs are likely to have a special rate attached to them.
It's also not recommended to include an ORDER BY in views, because views encapsulate the query -- no one will know what the default ordering is, and will likely include their own (waste of resources potentially).
you need to left join in the special rate.
If I recall the oracle syntax is like:
AND contract.contract_id = special_rate.contract_id (+)
but now special_rate.* can be null so:
+ special_rate.s_rate_amnt
will need to be:
+ coalesce(special_rate.s_rate_amnt,0)
We have a database that stores vehicle's gps position, date, time, vehicle identification, lat, long, speed, etc., every minute.
The following select pulls each vehicle position and info, but the problem is that returns the first record, and I need the last record (current position), based on date (datagps.Fecha) and time (datagps.Hora). This is the select:
SELECT configgps.Fichagps,
datacar.Ficha,
groups.Nombre,
datagps.Hora,
datagps.Fecha,
datagps.Velocidad,
datagps.Status,
datagps.Calleune,
datagps.Calletowo,
datagps.Temp,
datagps.Longitud,
datagps.Latitud,
datagps.Evento,
datagps.Direccion,
datagps.Provincia
FROM asigvehiculos
INNER JOIN datacar ON (asigvehiculos.Iddatacar = datacar.Id)
INNER JOIN configgps ON (datacar.Configgps = configgps.Id)
INNER JOIN clientdata ON (asigvehiculos.Idgroup = clientdata.group)
INNER JOIN groups ON (clientdata.group = groups.Id)
INNER JOIN datagps ON (configgps.Fichagps = datagps.Fichagps)
Group by Fichagps;
I need same result I'm getting, but instead of the older record I need the most recent
(LAST datagps.Fecha / datagps.Hora).
How can I accomplish this?
Add ORDER BY datagps.Fecha DESC, datagps.Hora DESC LIMIT 1 to your query.
I'm not sure why you are having any problems with this as Lex's answers seem good.
I would start putting ORDER BY's in your query so it puts them in an order, when it's showing the record you want as the first one in the list, then add the LIMIT.
If you want the most recent, then the following should be good enough:
ORDER BY datagps.Fecha DESC, datagps.Hora DESC
If you simply want the record that was added to the database most recently (irregardless of the date/time fields), then you could (assuming you have an auto-incremental primary key in the datagps table (I assume it's called dataID for this example)):
ORDER BY datagps.dataID DESC
If these aren't showing the data you want - then there is something missing from your example (maybe data-types aren't DATETIME fields? - if not - then maybe a CONVERT to change them from their current type before ORDERing BY would be a good idea)
EDIT:
I've seen the screenshot and I'm confused as to what the issue is still. That appears to be showing everything in order. Are you implying that there are many more than 5 records? How many are you expecting?
Do you mean: for each record returned, you want the one row from the table datagps with the latest date and time attached to the result? If so, how about this:
# To show how the query will be executed
# comment to return actual results
EXPLAIN
SELECT
configgps.Fichagps, datacar.Ficha, groups.Nombre, datagps.Hora, datagps.Fecha,
datagps.Velocidad, datagps.Status, datagps.Calleune, datagps.Calletowo,
datagps.Temp, datagps.Longitud, datagps.Latitud, datagps.Evento,
datagps.Direccion, datagps.Provincia
FROM asigvehiculos
INNER JOIN datacar ON (asigvehiculos.Iddatacar = datacar.Id)
INNER JOIN configgps ON (datacar.Configgps = configgps.Id)
INNER JOIN clientdata ON (asigvehiculos.Idgroup = clientdata.group)
INNER JOIN groups ON (clientdata.group = groups.Id)
INNER JOIN datagps ON (configgps.Fichagps = datagps.Fichagps)
########### Add this section
LEFT JOIN datagps b ON (
configgps.Fichagps = b.Fichagps
# wrong condition
#AND datagps.Hora < b.Hora
#AND datagps.Fecha < b.Fecha)
# might prevent indexes to be used
AND (datagps.Fecha < b.Fecha OR (datagps.Fecha = b.Fecha AND datagps.Hora < b.Hora))
WHERE b.Fichagps IS NULL
###########
Group by configgps.Fichagps;
Similar question here only that that one uses outer joins.
Edit (again):
The conditions are wrong so corrected it. Can you show us the output of the above EXPLAIN query so we can pinpoint where the bottle neck is?
As hurikhan77 said, it will be better if you could convert both of the the columns into a single datetime field - though I'm guessing this would not be possible for your case (since your database is already being used?)
Though if you can convert it, the condition (on the join) would become:
AND datagps.FechaHora < b.FechaHora
After that, add an index for datagps.FechaHora and the query would be fast(er).
What you probably want is getting the maximum of (Fecha,Hora) per grouped dataset? This is a little complicated to accomplish with your column types. You should combine Fecha and Hora into one column of type DATETIME. Then it's easy to just SELECT MAX(FechaHora) ... GROUP BY Fichagps.
It could have helped if you posted your table structure to understand the problem.
So I decided to try out PostgreSQL instead of MySQL but I am having some slight conversion problems. This was a query of mine that samples data from four tables and spit them out all in on result.
I am at a loss of how to convey this in PostgreSQL and specifically in Django but I am leaving that for another quesiton so bonus points if you can Django-fy it but no worries if you just pure SQL it.
SELECT links.id, links.created, links.url, links.title, user.username, category.title, SUM(votes.karma_delta) AS karma, SUM(IF(votes.user_id = 1, votes.karma_delta, 0)) AS user_vote
FROM links
LEFT OUTER JOIN `users` `user` ON (`links`.`user_id`=`user`.`id`)
LEFT OUTER JOIN `categories` `category` ON (`links`.`category_id`=`category`.`id`)
LEFT OUTER JOIN `votes` `votes` ON (`votes`.`link_id`=`links`.`id`)
WHERE (links.id = votes.link_id)
GROUP BY votes.link_id
ORDER BY (SUM(votes.karma_delta) - 1) / POW((TIMESTAMPDIFF(HOUR, links.created, NOW()) + 2), 1.5) DESC
LIMIT 20
The IF in the select was where my first troubles began. Seems it's an IF true/false THEN stuff ELSE other stuff END IF yet I can't get the syntax right. I tried to use Navicat's SQL builder but it constantly wanted me to place everything I had selected into the GROUP BY and that I think it all kinds of wrong.
What I am looking for in summary is to make this MySQL query work in PostreSQL. Thank you.
Current Progress
Just want to thank everybody for their help. This is what I have so far:
SELECT links_link.id, links_link.created, links_link.url, links_link.title, links_category.title, SUM(links_vote.karma_delta) AS karma, SUM(CASE WHEN links_vote.user_id = 1 THEN links_vote.karma_delta ELSE 0 END) AS user_vote
FROM links_link
LEFT OUTER JOIN auth_user ON (links_link.user_id = auth_user.id)
LEFT OUTER JOIN links_category ON (links_link.category_id = links_category.id)
LEFT OUTER JOIN links_vote ON (links_vote.link_id = links_link.id)
WHERE (links_link.id = links_vote.link_id)
GROUP BY links_link.id, links_link.created, links_link.url, links_link.title, links_category.title
ORDER BY links_link.created DESC
LIMIT 20
I had to make some table name changes and I am still working on my ORDER BY so till then we're just gonna cop out. Thanks again!
Have a look at this link GROUP BY
When GROUP BY is present, it is not
valid for the SELECT list expressions
to refer to ungrouped columns except
within aggregate functions, since
there would be more than one possible
value to return for an ungrouped
column.
You need to include all the select columns in the group by that are not part of the aggregate functions.
A few things:
Drop the backticks
Use a CASE statement instead of IF() CASE WHEN votes.use_id = 1 THEN votes.karma_delta ELSE 0 END
Change your timestampdiff to DATE_TRUNC('hour', now()) - DATE_TRUNC('hour', links.created) (you will need to then count the number of hours in the resulting interval. It would be much easier to compare timestamps)
Fix your GROUP BY and ORDER BY
Try to replace the IF with a case;
SUM(CASE WHEN votes.user_id = 1 THEN votes.karma_delta ELSE 0 END)
You also have to explicitly name every column or calculated column you use in the GROUP BY clause.