Hello! I have two tables: trips and stations, and I'm trying to print the ID and name from a distinct station along with the total number of rides from that station.
The ID and name come from the stations table, while the number of trips comes from the trips table, so I'd went ahead and created a query to:
SELECT id, name and num_rides
FROM (SELECT COUNT (*) num_rides FROM tableB AS b) AS num_rides
INNER JOIN tableA AS a ON a.station_id = b.start_station_id
The problem is in the JOIN statement of the outer query, where it doesn't seem to recognize the "b" alias for my table, which I aliased in the inner query.
I tried running the queries separately, and they both work fine. I'm assuming then, that the problem is that the computer doesn't remember my inner query alias on the outer query, but that doesn't make much sense, does it?
Error states: "Unrecognized name: trips" ---> trips being the alias I used for table B.
SELECT
station_id,
name,
num_of_rides AS num_of_rides_starting_at
FROM
(
SELECT
start_station_id,
COUNT(*) number_of_rides
FROM
bigquery-public-data.new_york_citibike.citibike_trips AS trips
GROUP BY
trips.start_station_id
)
AS num_of_rides
INNER JOIN
bigquery-public-data.new_york_citibike.citibike_stations AS stations ON stations.station_id = trips.start_station_id
ORDER BY num_of_rides DESC ```
I believe the issue is that the "trips" alias is only active inside the parentheses. Try naming that whole select statement and referencing that name.
SELECT
station_id,
name,
num_of_rides AS num_of_rides_starting_at
FROM
(
SELECT
start_station_id,
COUNT(*) number_of_rides
FROM
bigquery-public-data.new_york_citibike.citibike_trips AS trips
GROUP BY
trips.start_station_id
) NeedNameHere
AS num_of_rides
INNER JOIN
bigquery-public-data.new_york_citibike.citibike_stations AS stations
ON stations.station_id = NeedNameHere.start_station_id
ORDER BY num_of_rides DESC
Hope this may help
SELECT
station_id, /*from table: citibike_stations */
name, /*from table: citibike_trips */
number_of_rides AS number_of_rides_starting_at_station /*from table: station_num_trips*/
FROM
(SELECT
start_station_id,
COUNT(*) number_of_rides
FROM `bigquery-public-data.new_york_citibike.citibike_trips`
GROUP BY
start_station_id
)
AS station_num_trips
INNER JOIN
`bigquery-public-data.new_york_citibike.citibike_stations`
ON
station_id = start_station_id
ORDER BY
number_of_rides DESC
Related
I have 2 tables: 1st is comment, 2nd is rating
SELECT * FROM comment_table a
INNER JOIN (SELECT comment_id, SUM(rating_value) AS total_rating FROM rating_table GROUP BY comment_id) b
ON a.comment_id = b.comment_id
ORDER BY b.total_rating DESC
I tried the above SQL but doesn't work!
Object is to display a list of comments order by rating points of each comments.
SELECT s.* FROM (
SELECT * FROM comment_table a
INNER JOIN (SELECT comment_id, SUM(rating_value) AS total_rating FROM rating_table GROUP BY comment_id) b
ON a.comment_id = b.comment_id
) AS s
ORDER BY s.total_rating DESC
Nest it inside an another select. It will then output the data in the correct order.
I have a problem
I have 2, same tables. My select should show this two columns and the last one "sup_cr" should be counted.
sup_id, sup_name, sup_cr.
This is my query without inner join. But i don't know how to use a inner join in this query.
SELECT sup.sup_id,
sup.sup_name_en AS name,
(SELECT COUNT (sup_cr.sup_id_from)
FROM t_sup_supplier AS sup_cr
WHERE sup_cr.sup_id_from = sup.sup_id ) AS cr_numbers
FROM t_sup_supplier AS sup
Sorry for my english.
You don't need a join or aggregation. You can use a window function:
SELECT sup.sup_id, sup.sup_name_en AS name,
COUNT(*) OVER (PARTITION BY sup_id) AS cr_numbers
FROM t_sup_supplier sup;
You could rephrase this a join using:
SELECT
sup.sup_id,
sup.sup_name_en AS name,
COALESCE(sup_cr.cnt, 0) AS cr_numbers
FROM t_sup_supplier
LEFT JOIN
(
SELECT sup_id_from, COUNT(*) AS cnt
FROM t_sup_supplier
GROUP BY sup_id_from
) sup_cr
ON sup_cr.sup_id_from = sup.sup_id;
select year, gender, max(nHospitalizations) from (select TO_CHAR(i.since, 'YYYY') as year, u.gender, h.name,count(h.name) as nHospitalizations from hospital h
join hospitalization i on i.hospital = h.name
join person u on i.person = u.numberID
group by TO_CHAR(i.since, 'YYYY'), u.gender, h.name)
group by year, gender
order by year desc, gender asc
;
I have this query, and it's pretty much doing what I want it too, except, I want to know the hospital name with the most hospitalizations per year, but when I add the h.name to the select, SQL makes me add it to the outer group by, which would mean I would be getting the count per year, gender and hospital name like in the subquery, instead of the hospital with most hospitalizations per year and gender, how can I add the h.name to the outer query without adding it to the outer group by?
Never use commas in the FROM clause. Always use proper, explicit, standard, readable JOIN syntax.
You want to use window functions for this:
select *
from (select count(*) as nHospitalizations, to_char(i.since, 'YYYY') as year,
u.gender, h.name,
row_number() over (partition by min(i.since) order by count(*) desc) as seqnum
from hospital h join
hospitalization i
i.hospital = h.name join
person u
on i.person = u.numberID
group by TO_CHAR(i.since, 'YYYY'), u.gender, h.name
) x
where serqnum = 1
Problem in general words: I need to select value from one table referenced to the most repeated values in another table.
Tables have this structure:
screenshot
screenshot2
The question is to find country which has the most results from sportsmen related to it.
First, INNER JOIN tables to have relation between result and country
SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id);
Then, I count how much time each country appear
SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id))
GROUP BY country
;
And got this screenshot3
Now it feels like I'm one step away from solution ))
I guess it's possible with one more SELECT FROM (SELECT ...) and MAX() but I can't wrap it up?
ps:
I did it with doubling the query like this but I feel like it's so inefficient if there are millions of rows.
SELECT country
FROM (SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id)
) GROUP BY country
)
WHERE highest_participation = (SELECT MAX(highest_participation)
FROM (SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id)
) GROUP BY country
))
Also I did it with a view
CREATE VIEW temp AS
SELECT country as country_with_most_participations, COUNT(country) as country_participate_in_#_comp
FROM(
SELECT country, competition_id FROM result
INNER JOIN sportsman USING(sportsman_id)
)
GROUP BY country;
SELECT country_with_most_participations FROM temp
WHERE country_participate_in_#_comp = (SELECT MAX(country_participate_in_#_comp) FROM temp);
But not sure if it's easiest way.
If I understand this correctly you want to rank the countries per competition count and show the highest ranking country (or countries) with their count. I suggest you use RANK for the ranking.
select country, competition_count
from
(
select
s.country,
count(*) as competition_count,
rank() over (order by count(*) desc) as rn
from sportsman s
inner join result r using (sportsman_id)
group by s.country
) ranked_by_count
where rn = 1
order by country;
If the order of the result rows doesn't matter, you can shorten this to:
select s.country, count(*) as competition_count
from sportsman s
inner join result r using (sportsman_id)
group by s.country
order by count(*) desc
fetch first rows with ties;
You seem to be overcomplicating this. Starting from your existing join query, you can aggregate, order the results and keep the top row(s) only.
select s.country, count(*) cnt
from sportsman s
inner join result r using (sportsman_id)
group by s.country
order by cnt desc
fetch first 1 row with ties
Note that this allows top ties, if any.
SELECT country
FROM (SELECT country, COUNT(country) AS highest_participation
FROM (SELECT competition_id, country FROM result
INNER JOIN sportsman USING (sportsman_id)
) GROUP BY country
order by 2 desc
)
where rownum=1
This seems like a basic action in SQL, but it has me stumped.
I have about 2 different subqueries, each grouped by LOCATION_ID that contain a date column. For example, one query includes a listing of WORKORDER records while another query pulls records from the NOTE table. Both of these queries includes a join to the LOCATION table allowing me to group by LOCATION_ID.
My goal is to pull the latest date of contact at that particular location and that can be in the form of a workorder, note date, followup date, etc. which are stored in different tables. So ideally I would have a query grouped by LOCATION_ID that shows the latest date of contact for that location.
I would post SQL but I don't have anything that is currently working for me. Any ideas on how to approach this type of scenario?
Thanks!
SELECT
L.LOCATION_ID, Max(MaxDate)
FROM
LOCATION AS L
LEFT JOIN
(SELECT
LOCATION_ID, Max(dbo.LeadNote.NoteDate) AS MaxDate
FROM
LeadNote
INNER JOIN
LOCATION ON LeadNote.LOCATION_ID = LOCATION.LOCATION_ID
GROUP BY
LOCATION_ID) T1 ON L.LOCATION_ID = T1.CONTACTLOCATION_LOCATION_ID
LEFT JOIN
(SELECT
LOCATION_ID, Max(dbo.WORKORDER.WORKORDER_DATECREATED) AS MaxDate
FROM
WORKORDER
INNER JOIN
LOCATION ON LOCATION_ID = WORKORDER_LOCATION_ID
GROUP BY
LOCATION_ID) T2 ON L.LOCATION_ID = T2.CONTACTLOCATION_LOCATION_ID`
Perhaps you could try using UNION to get a single sql result, then wrap it and give it an alias, and then apply a MAX on the field you wish, which both queries return. Keep in mind that to use UNION both queries must return the same set of field names.
Ex:
Query A:
Select a, b, c from T1 where....
Query B:
Select a, f, e from T2 where...
you would have:
SELECT MAX(e)
FROM
(
(Select a, b, c, NULL as f, NULL as e from T1 where....)
UNION
(Select a, NULL as b, NULL as c, f, e from T2 where...)
) t
If you need to use a join you can use a case statement to fetch the larger date.
SELECT
L.LOCATION_ID,
(CASE WHEN(T2.MaxDate IS NULL OR T1.MaxDate > T2.MaxDate)
THEN T1.MaxDate
ELSE T2.MaxDate
END) MaxDate
...
Try:
SELECT
L.LOCATION_ID, Max(MaxDate)
FROM
(
(
SELECT
LOCATION_ID, Max(LeadNote.NoteDate) AS MaxDate
FROM
LeadNote
JOIN
LOCATION
ON
LeadNote.LOCATION_ID = LOCATION.LOCATION_ID
GROUP BY
LOCATION_ID
)
UNION
(
SELECT
LOCATION_ID, Max(WORKORDER.WORKORDER_DATECREATED) AS MaxDate
FROM
WORKORDER
JOIN
LOCATION ON LOCATION_ID = WORKORDER_LOCATION_ID
GROUP BY
LOCATION_ID
)
)
It may need a little tweaking...but kudos to the comment by #DrCopyPaste if this works :)
You can do this with a simple join and a case statement:
SELECT
L.LOCATION_ID,
CASE WHEN(Max(LeadNote.NoteDate) IS NULL OR Max(LeadNote.NoteDate) > Max(WORKORDER.WORKORDER_DATECREATED)
THEN Max(LeadNote.NoteDate)
ELSE Max(WORKORDER.WORKORDER_DATECREATED) end AS maxDate
FROM
LOCATION AS L
LEFT JOIN LeadNote ON LeadNote.LOCATION_ID = LOCATION.LOCATION_ID
LEFT JOIN WORKORDER ON L.LOCATION_ID = WORKORDER_LOCATION_ID
GROUP BY L.LOCATION_ID