I am trying to give different cities a "score" from 1 to 5 based on multiple different criteria to eventually add up the scores and make a decision about which city is the best.
The table "international_tobacco_alcohol" contains values of the percentage of income that residents spend on alcohol and tobacco. I want to sort the results into 5 bins where 1 is the lowest percentage spending, 5 is the highest.
I added a "sort_order" column
ALTER TABLE international_tobacco_alcohol ADD COLUMN sort_order INT DEFAULT NULL;
SET #x = 0;
UPDATE international_tobacco_alcohol SET sort_order = (#x:=#x+1)
ORDER BY spent_on_alcohol_and_tobacco;
SELECT * FROM international_tobacco_alcohol;
And then I wanted to add the column "score" but I don't know how to do it correctly. I have tried basically every variation I can think of:
ALTER TABLE international_tobacco_alcohol ADD COLUMN score INT DEFAULT NULL;
UPDATE international_tobacco_alcohol
SET score = CASE
WHEN sort_order < .2*MAX(sort_order) THEN 1
WHEN sort_order=> .2*MAX(sort_order)and <.4*MAX(sort_order) THEN 2
WHEN sort_order=> .4*MAX(sort_order)and <.6*MAX(sort_order) THEN 3
WHEN sort_order=> .6*MAX(sort_order)and <.8*MAX(sort_order) THEN 4
WHEN sort_order=> .8*MAX(sort_order)and =<MAX(sort_order) THEN 5
END;
I want the CASE WHEN clause to be in proportion to the total number of rows, not a predefined value, so that it can be recreatable and used with new data.
I appreciate some help. If I could create the score without the intermediate step of creating the "sort_order" column that would be great too.
`
You don't need the [sort_order] by [spent_on_alcohol_and_tobacco].
An alternative is to use RANK() function or DENSE_RANK();
I don't know the columns but you can do something like this:
SELECT [col_1], [col_2]
,RANK() OVER
(PARTITION BY [Location] ORDER BY [spent_on_alcohol_and_tobacco] DESC) AS Rank
FROM [international_tobacco_alcohol]
Hope this helps
Related
The SQL query is :
Select ProductName from Products;
The above query returns 5000 rows.
How can the result of 5000 rows be divided into two result sets of 2500 rows each,.i.e., one result set from 1 to 2500 and the other from 2501 to 5000?
Note:
Here ProductName is the primary Key.No ProductID column is present in the table.
It can be done either in the back end or in the front end.
An approach that works for mySQL (based on this answer https://stackoverflow.com/a/4741301/14015737):
Upper half
SELECT *
FROM (
SELECT test.*, #counter := #counter +1 counter
FROM (select #counter:=0) initvar, test
ORDER BY num
) X
WHERE counter <= round(50/100 * #counter);
ORDER BY num;
Lower half
Invert the sort order and remove the rounding
SELECT *
FROM (
SELECT test.*, #counter := #counter +1 counter
FROM (select #counter:=0) initvar, test
ORDER BY num DESC
) X
WHERE counter <= (50/100 * #counter);
ORDER BY num;
In case of an uneven number of records, the middle record is added to the upper half in this example. If you want it the other way around, move the round() to the other statement. If you don't want it at all, remove round().
Dbfiddle example: https://dbfiddle.uk/?rdbms=mysql_5.7&fiddle=fb70eae0f7f1434a24099b5bb19f0878
If you know the numbers that you want, just use limit:
select ProductName
from Products
order by id
And then either:
limit 2500
limit 2500 offset 2499
If you simply want the results split into half, then you can use:
select t.*
from (select t.*,
ntile(2) over (order by <primary key>) as tile
from t
) t
where tile = 1; -- or 2 for the other half
The easiest and probably fastest approach is to use the table's primary key if you are fine with getting the rows in its order.
Run
select productname, id from products order by id;
and fetch 2500 rows. Then with the last ID, say ID 3456, run
select productname, id from products where id > 3456 order by id;
and fetch 2500 rows again. Etc.
UPDATE: Seeing I got a downvote for this, I'll better explain :-)
The query returns 5000 rows now and the OP doesn't want that many rows, so they want to cut this in halves. But the query may well return 10000 rows next year. Will the OP suddenly be fine with getting 5000 rows at once? This doesn't seem likely. It is more likely that there is an amount of rows that shall not be surpassed. This is why I cut the amount into slices of 2500.
The other approach to number all rows and return the first n rows has a severe drawback: All rows must be read again. Even if it is decided to cut the result in chunks of 100 each, everytime all rows must be read, sorted, numbered, fetched from. Reading all rows from a table and sorting all these rows is a lot of work for a DBMS.
I have a table with the following columns:
id | revisit (bool) | FL (decimal) | FR (decimal) | RL (decimal) | RR (decimal) | date
I need to write a SELECT statement that will ORDER BY on multiple columns, depending on the value of the 'revisit' field.
ORDER BY 'revisit' DESC - records with this field having the value 1 will be first, and 0 will be after
If 'revisit' = 1 order by the lowest value that exists in FL, FR, RL and RR. So if record 1 has values 4.6, 4.6, 3.0, 5.0 in these fields, and record 2 has values 4.0, 3.1, 3.9, and 2.8 then record 2 will be returned first as it holds a lowest value within these four columns.
If 'revisit' = 0 then order by date - oldest date will be first.
So far I have the 'revisit' alone ordering correctly, and ordering by date if 'revisit' = 0, but ordering by the four columns simultaneously when 'revisit' = 1 does not.
SELECT *
FROM vehicle
ORDER BY
`revisit` DESC,
CASE WHEN `revisit` = 1 THEN `FL` + `FR` + `RR` + `RL` END ASC,
CASE WHEN `revisit` = 0 THEN `date` END ASC
Instead it seems to be ordering by the total of the four columns (which would make sense given addition symbols), so how do I ORDER BY these columns simultaneously, as individual columns, rather than a sum.
I hope this makes sense and thanks!
In your current query, you order by the sum of the four columns. You can use least to get the lowest value, so your order by clause could look like:
SELECT *
FROM vehicle
ORDER BY
`revisit` DESC,
CASE WHEN `revisit` = 1 THEN LEAST(`FL`, `FR`, `RR`, `RL`) END ASC,
CASE WHEN `revisit` = 0 THEN `date` END ASC
Of course this would sort only by the lowest value. If two rows would both share the same lowest value, there is no sorting on the second-lowest value. To do that is quite a bit harder, and I didn't really get from your question whether you need that.
I have for example a query with return something as it
route value
1 3
2 2
3 4
4 5
5 1
then I need to put in 2 textbox the max and the min route so in sql this would be
select top 1 route from table where value=(select max(value) from table)
I add a image done in excel, how this would be.
I believe this is so easy but I dont have idea how to get it.
I got using expression, this was extactly expression
="Route "+
Convert.ToString (
Lookup(max(fields!value.Value),fields!value.Value ,fields!route.Value,"mydataset")
)
changing max for min, for the other...
thanks everyone.
I believe the query you're looking for would be:
With Min_Max_CTE as (
Select MIN(value) as Min_Value
, MAX(value) as Max_Value
From Table
)
Select Top 1 'Min' as Type
, T.route
, T.value
From Table T
Inner Join Min_Max_CTE CTE
on T.value = CTE.Min_Value
Union All
Select Top 1 'Max' as Type
, T.route
, T.value
From Table T
Inner Join Min_Max_CTE CTE
on T.value = CTE.Max_Value
Order by Type desc --This will put the Min Route first followed by the Max Route
Then, put that query into a dataset, and then create a tablix and use the Type, route, and value fields to return the minimum route and the maximum route. It should end up being set up just like your excel section with the min and max routes above.
You can do this SSRS by using a couple of separate tables. Your example data:
And two tables in the Designer:
Since the tables only have header rows, only the first row in the table will be displayed.
To make sure we get the MAX and MIN values in the two tables, each table needs to order its Dataset appropriately, i.e. by Value by descending and ascending respectively.
MAX table:
MIN table:
Which gives your expected result:
I have a query which works great given that the result is only one number, but now I need to allow for multiple rows to be returned and the query cannot handle that because it uses a user define variable... here is original procedure
CREATE DEFINER=`root`#`%` PROCEDURE `MapRank`(pTankID bigint,pMapID int, pColor int(2))
BEGIN
SET #RankNumber:=0;
select RankNumber
from
(select
TankID,
#RankNumber:=#RankNumber+1 as RankNumber,
MapID,
Color
from MAPDATA WHERE MapID = pMapID order by Rank DESC, TotalPP DESC) Query1 where TankID = pTankID AND COLOR = pColor ;
END
this returns a single number, essentially counting the number of records down it is, giving me the "row" location.
now I need to change it to give me all rows with out the where for mapid and color, so that I can see all ranks for all mapid/color combo
this is what I have that currently does not work
SET #RankNumber:=0;
select
RankNumber,MapID,COlor
from
(select
TankID,
#RankNumber:=#RankNumber + 1 as RankNumber,
MapID,
Color
from
MAPDATA
order by TotalPP DESC) Query1
where
TankID = 18209 ORDER BY RankNumber
the yielding query result looks as such:
1062 3 1
3544 3 0
6717 17 1
6752 17 3
7453 3 2
7860 17 0
7984 17 2
9220 3 3
if I run manually lets say, map id 3 and color 3 which says rank number is 9220 with the FIRST query I get this
6022
I need this to be able to be done possibly from multiple MySQL connections so ideally done without use of a temporary variable since its possible another person may come in and use that... any help would be great.
After digging and messing more I have found the solution to be to set the variable back to zero from within the outer select.. and since user defined variable are connection level and I utilize pooling we should never have an issue.
SET #RankNumber:=0;
select
RankNumber,MapID,COlor, #RankNumber:=0
from
(select
TankID,
#RankNumber:=#RankNumber + 1 as RankNumber,
MapID,
Color
from
MAPDATA
order by MapID, Rank DESC, TotalPP DESC ) Query1
where
TankID = pTankID ORDER BY RankNumber;
Im trying to get a result set that contains the 10 values that are closest to, in this case, the number 3.
I have a database that has values in a column named rated which can be 1,2,3,4 or 5. What im trying to do is query the database and return the first 10 rows that have the values closest to 3. The values can be above 3 or below 3. I should note that these values in the rated column are floats.
I then need to sort these rows in order so that rows with value of 3 are first and then the row with lowest offset (+/-) from 3.
Is there any SQL query that can return atleast the result set of values closest to 3 ? or am i going to have to return the whole db and sort it myself?
To get the first 10 rows with highest value down i used the statement
SELECT * FROM tabs ORDER BY 5 DESC LIMIT 10";
5 refers to the column rated
Is there some way to modify this to do what i want ?
Thanks
If I understand your problem correctly, this should do the trick:
select *
from tabs
order by abs(`rated` - 3) asc
limit 10
Note that it sorts by the difference in ascending order, so those with a difference of 0 will come first.
SELECT * FROM tabs ORDER BY ABS(3 - Rate) ASC LIMIT 10
If I got right what you need try:
select *
from (
select
case when -(3-rated) > 0 then -(3-rated) else (3-rated) end as distance,
tabs.*
from tabs
) subsel
order by distance
limit 10