I'm creating a simple game and I want to get the best lap_time for each type in the db.
However, my query returns the wrong player_id (3 in second row) and total_ranks (all ranks instead of count by type).
Link to sqlfiddle: http://sqlfiddle.com/#!9/a0c36a/2
Desired result
+--------+-----+-------+------------+----------------+-------------+
| level | cp | type | player_id | MIN(lap_time) | total_ranks |
+--------+-----+-------+------------+----------------+-------------+
| 1 | 1 | 0 | 1 | 10.5 | 4 |
| 1 | 1 | 1 | 2 | 10.45 | 3 |
+--------+-----+-------+------------+----------------+-------------+
Is it possible to make it work in 1 query or do I need at least 2?
Fiddle
Same concept as Tim, but with Total_Ranks column
SELECT level, cp, R.type, player_id, MinTime, Total_Ranks
FROM runtimes R
JOIN (SELECT TYPE, MIN(LAP_TIME) MinTime, Count(*) Total_Ranks
FROM RUNTIMES
GROUP BY TYPE) T on R.Type = T.Type
and R.lap_time = T.MinTime
WHERE level=1
AND cp=1
One canonical way to solve this problem in MySQL is to use a subquery to identify the minimum lap time for each type. Then join your full table to this to obtain the entire record. Note that a nice side effect of this approach is that we also get back ties if a given type have more than one person sharing the minimum lap time.
SELECT r1.*, r2.total_ranks
FROM runtimes r1
INNER JOIN
(
SELECT type, MIN(lap_time) AS min_lap_time, COUNT(*) AS total_ranks
FROM runtimes
GROUP BY type
) r2
ON r1.type = r2.type AND
r1.lap_time = r2.min_lap_time
Here is a link to your updated Fiddle:
SQLFiddle
Related
I have a table where it stores the types of discounts that a user can have.
Some users will get the standard discount, but some will get a bigger and better discount. For users who have the biggest and best discount, there will be two records in the database, one for the default discount and the other for the biggest and best discount. The biggest and best discount will be preferred in the search.
I would like to do a SELECT that would return the record with the highest discount and if you don't find it, return it with the standard discount for me to avoid making two queries in the database or having to filter in the source code.
Ex:
| id | user_id | country | discount | cashback | free_trial |
|-----------------------------------------------------------------------|
| 1 | 1 | EUA | DEFAULT | 10 | false |
| 2 | 1 | EUA | CHRISTMAS | 20 | true |
| 3 | 3 | EUA | DEFAULT | 10 | false |
SELECT *
FROM users
WHERE country = 'EUA'
AND (discount = 'CHRISTMAS' OR discount = 'DEFAULT');
In this example above for user 1 it would return the record with the discount equal to "CHRISTMAS" and for user 3 it would return "DEFAULT" because it is the only one that has. Can you help me please?
You can use the row_number() window function to do this. This function includes a PARTITION BY that lets you start the numbering over with each user, as well as it's own ORDER BY that lets you determine which rows will sort first within each user/partition.
Then you nest this inside another SELECT to limit to rows where the row_number() result is 1 (the discount that sorted best):
SELECT *
FROM (
SELECT *, row_number() OVER (PARTITION BY id, ORDER BY cashback desc) rn
FROM users
WHERE country = 'EUA'
) u
WHERE rn = 1
You could also use a LATERAL JOIN, which is usually better than the correlated join in the other answer, but not as good as the window function.
You can using GROUP BY to do it
SELECT u1.*
FROM users u1
JOIN
(
SELECT COUNT(id) AS cnt,user_id
FROM users WHERE country = 'EUA'
GROUP BY user_id
) u2 ON u1.user_id=u2.user_id
WHERE IF(u2.cnt=1,u1.discount='DEFAULT',u1.discount='CHRISTMAS')
DB Fiddle Demo
I have two tables, one is an index (or map) which helps when other when pulling queries.
SELECT v.*
FROM smv_ v
WHERE (SELECT p.network
FROM providers p
WHERE p.provider_id = v.provider_id) = 'RUU='
AND (SELECT p.va
FROM providers p
WHERE p.provider_id = v.provider_id) = 'MjU='
LIMIT 1;
Because we do not know the name of the column that holds the main data, we need to look it up, using the provider_id which is in both tables, and then query.
I am not getting any errors, but also no data back. I have spent the past hour trying to put this on sqlfiddle, but it kept crashing, so I just wanted to check if my code is really wrong, hence the crashing?
In the above example, I am looking in the providers table for column network, where the provider_id matches, and then use that as the column on smv.
I am sure i have done this before just like this, but after the weekend trying I thought i would ask on here.
Thanks in Advance.
UPDATE
Here is an example of the data:
THis is the providers, this links so no matter what the name of the column on the smv table, we can link them.
+---+---+---------------+---------+-------+--------+-----+-------+--------+
| | A | B | C | D | E | F | G | H |
+---+---+---------------+---------+-------+--------+-----+-------+--------+
| 1 | 1 | Home | network | batch | bs | bp | va | bex |
| 2 | 2 | Recharge | code | id | serial | pin | value | expire |
+---+---+---------------+---------+-------+--------+-----+-------+--------+
In the example above, G will mean in the smv column for recharge we be value. So that is what we would look for in our WHERE clause.
Here is the smv table:
+---+---+-----------+-----------+---+----+---------------------+-----+--+
| | A | B | C | D | E | F | value | va |
+---+---+-----------+-----------+---+----+---------------------+-----+--+
| 1 | 1 | X2 | Home | 4 | 10 | 2016-09-26 15:20:58 | | 7 |
| 2 | 2 | X2 | Recharge | 4 | 11 | 2016-09-26 15:20:58 | 9 | |
+---+---+-----------+-----------+---+----+---------------------+-----+--+
value in the same example as above would be 9, or 'RUU=' decoded.
So we do not know the name of the rows, until the row from smv is called, once we have this, we can look up what column name we need to get the correct information.
Hope this helps.
MORE INFO
At the point of triggering, we do not know what the row consists of the right data because some many of the fields would be empty. The map is there to help we query the right column, to get the right row (smv grows over time depending on whats uploaded.)
1) SELECT p.va FROM providers p WHERE p.network = 'Recharge' ;
2) SELECT s.* FROM smv s, providers p WHERE p.network = 'Recharge';
1) gives me the correct column I need to look up and query smv, using the above examples it would come back with "value". So I need to now look up, within the smv table, C = Recharge, and value = '9'. This should bring me back row 2 of the smv table.
So individually both 1 and 2 queries work, but I need them put together so the query is done on the database server.
Hope this gives more insight
Even More Info
From reading other posts, which are not really doing what I need, i have come up with this:
SELECT s.*
FROM (SELECT
(SELECT p.va
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS net,
(SELECT p.bex
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS bex
FROM dh_smv_providers) AS val, dh_smv_ s
WHERE s.provider_id = 'vodaphone' AND net = '20'
ORDER BY from_base64(val.bex) DESC;
The above comes back blank, but if i replace net, in the WHERE clause with a column I know exists, I do get the results expected:
SELECT s.*
FROM (SELECT
(SELECT p.va
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS net,
(SELECT p.bex
FROM dh_smv_providers p
WHERE p.provider_name = 'vodaphone'
LIMIT 1) AS bex
FROM dh_smv_providers) AS val, dh_smv_ s
WHERE s.provider_id = 'vodaphone' AND value = '20'
ORDER BY from_base64(val.bex) DESC;
So what I am doing wrong, which is net, not showing the value derived from the subquery "value" ?
Thanks
SELECT
v.*,
p.network, p.va
FROM
smv_ v
INNER JOIN
providers p ON p.provider_id = v.provider_id
WHERE
p.network = 'RUU=' AND p.va = 'MjU='
LIMIT 1;
The tables talk to each other via the JOIN syntax. This completely circumvents the need (and limitations) of sub-selects.
The INNER JOIN means that only fully successful matches are returned, you may need to adjust this type of join for your situation but the SQL will return a row of all v columns where p.va = MjU and p.network = RUU and p.provider_id = v.provider_id.
What I was trying to explain in comments is that subqueries do not have any knowledge of their outer query:
SELECT *
FROM a
WHERE (SELECT * FROM b WHERE a)
AND (SELECT * FROM c WHERE a OR b)
This layout (as you have in your question) is that b knows nothing about a because the b query is executed first, then the c query, then finally the a query. So your original query is looking for WHERE p.provider_id = v.provider_id but v has not yet been defined so the result is false.
I've written a query that builds a small table of information from a couple of data sources, it uses a self made table to reference the vehicle model for the final group by which is how the data needs to be viewed, however when I group by vehicle it misses out figures in the subquery column from the group by, i.e. if I group by Prefix it shows the correct numbers, grouped by Vehicle hides off some of the data.
The Prefix can relate to a couple of like vehicle models and hence the need to group by vehicle. Can anyone see what I've done wrong easily from the SQL query below please.
SELECT Vehicle, COUNT(`Chassis-No`) AS Stock,
ROUND((100/COUNT(`Chassis-No`)) * SUM(CASE WHEN `Vehicle Age` > '182' THEN 1 ELSE 0 END),1) AS Perc6Months,
ROUND((100/COUNT(`Chassis-No`)) * SUM(CASE WHEN `Vehicle Age` > '365' THEN 1 ELSE 0 END),1) AS Perc12Months,
(SELECT COUNT(VIN_Prefix) FROM Orderdownload
INNER JOIN VehicleMatrix ON (`VIN_Prefix` LIKE 'S%' AND Prefix = LEFT(`VIN_Prefix`,2)) OR (`VIN_Prefix` NOT LIKE 'S%' AND Prefix = LEFT(`VIN_Prefix`,1)) WHERE DealerCode = 'AA12345' AND `VIN_Prefix` = IF(LEFT(`Chassis-No`,1)='S',LEFT(`Chassis-No`,2),LEFT(`Chassis-No`,1))) As Qty
FROM DealerAgedStock
INNER JOIN VehicleMatrix AS VM
ON (`Chassis-No` LIKE 'S%' AND Prefix = LEFT(`Chassis-No`,2)) OR (`Chassis-No` NOT LIKE 'S%' AND Prefix = LEFT(`Chassis-No`,1))
WHERE `DL Dealer Code` = 'AA12345'
GROUP BY Vehicle
Grouped on Vehicle I get the following:
Vehicle | Perc6Months | Perc12Months | Qty
Mondeo | 37.5 | 0 | 2
Grouped on Prefix I get the following:
VIN_Prefix | Perc6Months | Perc12Months | Qty
S1 | 25 | 0 | 2
S2 | 50 | 0 | 2
Ideally it should look this this:
Vehicle | Perc6Months | Perc12Months | Qty
Mondeo | 37.5 | 0 | 4
Where S1 and S2 are relative to the Vehicle Mondeo, thus it gives me the first instance of subquery rather than adding them together.
My question is: why does the Group By not add the figures together properly from the subquery? I need it to add them to have the correct figures...
First of all, here is the sqlfiddle I made: http://sqlfiddle.com/#!2/b9d06c
I have 3 tables, project, document_template, and project_document.
The project table contains a project id and a name.
The document template table contains a document template id and a name for the template.
The project document table contains an id, and a project id and document template id associated with it, as well as a date when it was sent.
I'm trying to create a view that contains all combinations of project ids and document template ids, which I can do easily with a
CROSS JOIN
However, after that I would like to add an additional column to the view named 'last_sent' that contains the latest date at which a template is used with a project, and in order to do that it has to look at the information in the project_document table.
I've included an example in comments at the bottom of the sqlfiddle code to show how it should look.
I've tried adding different left joins to the end of the view query but can't seem to get it to show how I want it to. :(
Any help is greatly appreciated!
SETUP:
basically get your Cartesian Product.. then join the project_id's and document_template_id's to the most recent date.. that date needs to be in a separate select with the id for the project and doc_temp so that you can join it appropriately.. finally use coalesce on the date so that when theres null values you put in a blank
QUERY:
SELECT
t1.project_id , t1.document_template_id , COALESCE(t.last_sent, ' ') AS last_sent
FROM
( SELECT p.project_id, dt.document_template_id
FROM project p, document_template dt
GROUP BY project_id, document_template_id
) t1
LEFT JOIN
( SELECT project_id, document_template_id, MAX(sent_on) AS last_sent
FROM project_document
GROUP BY document_template_id
) t ON t.project_id = t1.project_id
AND t.document_template_id = t1.document_template_id;
OUTPUT:
+--------------+--------------------------+---------------------+
| project_id | document_template_id | last_sent |
+--------------+--------------------------+---------------------+
| 1 | 1 | |
| 1 | 2 | 2014-08-12 10:00:23 |
| 1 | 3 | 2014-07-11 08:12:40 |
| 2 | 1 | |
| 2 | 2 | |
| 2 | 3 | |
+--------------+--------------------------+---------------------+
DEMO
Try
SELECT
p.project_id,
dt.document_template_id,
MAX(pd.sent_on) AS last_sent
FROM project p
CROSS JOIN document_template dt
LEFT OUTER JOIN project_document pd
ON p.project_id=pd.project_id
AND dt.document_template_id=pd.document_template_id
GROUP BY p.project_id, dt.document_template_id
ORDER BY p.project_id, dt.document_template_id
If you want empty instead null use COALESCE(MAX(pd.sent_on), '') AS last_sent instead
When you use aggregate functions as MAX, you should point group target by GROUP BY clause. Else you will have only one returned row.
I am attempting to narrow results of an existing complex query based on conditional matches on multiple columns within the returned data set. I'll attempt to simplify the data as much as possible here.
Assume that the following table structure represents the data that my existing complex query has already selected (here ordered by date):
+----+-----------+------+------------+
| id | remote_id | type | date |
+----+-----------+------+------------+
| 1 | 1 | A | 2011-01-01 |
| 3 | 1 | A | 2011-01-07 |
| 5 | 1 | B | 2011-01-07 |
| 4 | 1 | A | 2011-05-01 |
+----+-----------+------+------------+
I need to select from that data set based on the following criteria:
If the pairing of remote_id and type is unique to the set, return the row always
If the pairing of remote_id and type is not unique to the set, take the following action:
Of the sets of rows for which the pairing of remote_id and type are not unique, return only the single row for which date is greatest and still less than or equal to now.
So, if today is 2011-01-10, I'd like the data set returned to be:
+----+-----------+------+------------+
| id | remote_id | type | date |
+----+-----------+------+------------+
| 3 | 1 | A | 2011-01-07 |
| 5 | 1 | B | 2011-01-07 |
+----+-----------+------+------------+
For some reason I'm having no luck wrapping my head around this one. I suspect the answer lies in good application of group by, but I just can't grasp it. Any help is greatly appreciated!
/* Rows with exactly one date - always return regardless of when date occurs */
SELECT id, remote_id, type, date
FROM YourTable
GROUP BY remote_id, type
HAVING COUNT(*) = 1
UNION
/* Rows with more than one date - Return Max date <= NOW */
SELECT yt.id, yt.remote_id, yt.type, yt.date
FROM YourTable yt
INNER JOIN (SELECT remote_id, type, max(date) as maxdate
FROM YourTable
WHERE date <= DATE(NOW())
GROUP BY remote_id, type
HAVING COUNT(*) > 1) sq
ON yt.remote_id = sq.remote_id
AND yt.type = sq.type
AND yt.date = sq.maxdate
The group by clause groups all rows that have identical values of one or more columns together and returns one row in the result set for them. If you use aggregate functions (min, max, sum, avg etc.) that will be applied for each "group".
SELECT id, remote_id, type, max(date)
FROM blah
GROUP BY remote_id, date;
I'm not whore where today's date comes in, but assumed that was part of the complex query that you didn't describe and I assume isn't directly relevant to your question here.
Try this:
SELECT a.*
FROM table a INNER JOIN
(
select remote_id, type, MAX(date) date, COUNT(1) cnt from table
group by remote_id, type
) b
WHERE a.remote_id = b.remote_id,
AND a.type = b.type
AND a.date = b.date
AND ( (b.cnt = 1) OR (b.cnt>1 AND b.date <= DATE(NOW())))
Try this
select id, remote_id, type, MAX(date) from table
group by remote_id, type
Hey Carson! You could try using the "distinct" keyword on those two fields, and in a union you can use Count() along with group by and some operators to pull non-unique (greatest and less-than today) records!