From: | Alexander Farber <alexander(dot)farber(at)gmail(dot)com> |
---|---|
To: | pgsql-general <pgsql-general(at)postgresql(dot)org> |
Subject: | Adding AVG to a JOIN |
Date: | 2018-04-23 08:58:45 |
Message-ID: | CAADeyWiM21RZVsc4McqydbRxE4sNvUp-xATehfkTqjcrqG8WSA@mail.gmail.com |
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Lists: | pgsql-general |
Hello,
in PostgreSQL 10.3 I run the following query to find top 10 players with
the best ELO rating:
# SELECT
u.elo,
u.uid,
s.given,
s.photo
FROM words_users u
JOIN words_social s USING (uid)
WHERE u.elo > 1500
-- take the most recent record from words_social (storing user details from
social networks)
AND NOT EXISTS (SELECT 1
FROM words_social x
WHERE s.uid = x.uid
AND x.stamp > s.stamp)
-- only show players who where active in the last week
AND EXISTS (SELECT 1
FROM words_moves
WHERE played > CURRENT_TIMESTAMP - INTERVAL '1 week'
AND action IN ('play', 'skip', 'swap', 'resign'))
ORDER BY u.elo DESC
LIMIT 10;
elo | uid | given |
photo
------+------+----------+------------------------------------------------------------------------------------------------------------
2078 | 1201 | Roman |
https://lh6.googleusercontent.com/-kNp75NGW6wo/AAAAAAAAAAI/AAAAAAAAABs/QN7rEc17JNc/photo.jpg
1952 | 2846 | дана |
https://avt-30.foto.mail.ru/mail/dance1011/_avatarbig?1523746018
1923 | 2808 | Ириша |
https://avt-24.foto.mail.ru/mail/irusy2277/_avatarbig?1518190793
1788 | 3479 | наталья | https://avt-5.foto.mail.ru/mail/leutan/_avatarbig
1749 | 3404 | ♕ OLGA ♕ |
https://avt-30.foto.mail.ru/mail/olgapinsk2/_avatarbig?1484081891
1733 | 3336 | Надежда |
https://avt-14.foto.mail.ru/mail/katerenyuk78/_avatarbig?1520366579
1724 | 1765 | ЕЛЕНА |
https://i.mycdn.me/image?id=805029440389&t=0&plc=API&ts=00&aid=1158060544&tkn=*looACpPtImwclHOmPBfnpuashFk
1717 | 3091 | андрей |
https://avt-11.foto.mail.ru/yandex.ru/maimun-11/_avatarbig?1453033064
1711 | 3000 | Алекс |
https://avt-20.foto.mail.ru/mail/taa113/_avatarbig?1495430756
1708 | 3991 | Кузнецов |
https://avt-10.foto.mail.ru/inbox/sobaka.58/_avatarbig?1353528572
(10 rows)
The above query works well and quick, but I need to add the average score
per move information to it.
Here is such a query for the best player
# SELECT AVG(score) FROM words_moves WHERE uid = 1201;
avg
---------------------
18.4803525523319868
However I am not sure, how to "marry" the 2 queries?
I have tried to add words_moves through another JOIN, but that does not
work:
# SELECT
u.elo,
u.uid,
AVG(m.score), -- how to add the player average score?
s.given,
s.photo
FROM words_users u
JOIN words_social s USING (uid)
JOIN words_moves m USING (uid)
WHERE u.elo > 1500
AND NOT EXISTS (SELECT 1
FROM words_social x
WHERE s.uid = x.uid
AND x.stamp > s.stamp)
AND EXISTS (SELECT 1
FROM words_moves
WHERE played > CURRENT_TIMESTAMP - INTERVAL '1 week'
AND action IN ('play', 'skip', 'swap', 'resign'))
ORDER BY u.elo DESC
LIMIT 10
;
ERROR: 42803: column "u.elo" must appear in the GROUP BY clause or be used
in an aggregate function
LINE 2: u.elo,
^
Please give me some hints, how to approach this.
Thank you!
Alex
P.S: Below are the 3 tables referenced above:
# \d words_users
Table "public.words_users"
Column | Type | Collation | Nullable |
Default
---------------+--------------------------+-----------+----------+------------------------------------------
uid | integer | | not null |
nextval('words_users_uid_seq'::regclass)
created | timestamp with time zone | | not null |
visited | timestamp with time zone | | not null |
ip | inet | | not null |
fcm | text | | |
apns | text | | |
adm | text | | |
motto | text | | |
vip_until | timestamp with time zone | | |
grand_until | timestamp with time zone | | |
banned_until | timestamp with time zone | | |
banned_reason | text | | |
elo | integer | | not null |
medals | integer | | not null |
coins | integer | | not null |
Indexes:
"words_users_pkey" PRIMARY KEY, btree (uid)
Check constraints:
"words_users_banned_reason_check" CHECK (length(banned_reason) > 0)
"words_users_elo_check" CHECK (elo >= 0)
"words_users_medals_check" CHECK (medals >= 0)
Referenced by:
TABLE "words_chat" CONSTRAINT "words_chat_uid_fkey" FOREIGN KEY (uid)
REFERENCES words_users(uid) ON DELETE CASCADE
TABLE "words_games" CONSTRAINT "words_games_player1_fkey" FOREIGN KEY
(player1) REFERENCES words_users(uid) ON DELETE CASCADE
TABLE "words_games" CONSTRAINT "words_games_player2_fkey" FOREIGN KEY
(player2) REFERENCES words_users(uid) ON DELETE CASCADE
TABLE "words_moves" CONSTRAINT "words_moves_uid_fkey" FOREIGN KEY (uid)
REFERENCES words_users(uid) ON DELETE CASCADE
TABLE "words_reviews" CONSTRAINT "words_reviews_author_fkey" FOREIGN
KEY (author) REFERENCES words_users(uid) ON DELETE CASCADE
TABLE "words_reviews" CONSTRAINT "words_reviews_uid_fkey" FOREIGN KEY
(uid) REFERENCES words_users(uid) ON DELETE CASCADE
TABLE "words_scores" CONSTRAINT "words_scores_uid_fkey" FOREIGN KEY
(uid) REFERENCES words_users(uid) ON DELETE CASCADE
TABLE "words_social" CONSTRAINT "words_social_uid_fkey" FOREIGN KEY
(uid) REFERENCES words_users(uid) ON DELETE CASCADE
# \d words_social
Table "public.words_social"
Column | Type | Collation | Nullable | Default
--------+------------------+-----------+----------+---------
sid | text | | not null |
social | integer | | not null |
given | text | | not null |
family | text | | |
photo | text | | |
lat | double precision | | |
lng | double precision | | |
stamp | integer | | not null |
uid | integer | | not null |
Indexes:
"words_social_pkey" PRIMARY KEY, btree (sid, social)
Check constraints:
"words_social_given_check" CHECK (given ~ '\S'::text)
"words_social_photo_check" CHECK (photo ~* '^https?://...'::text)
"words_social_social_check" CHECK (0 < social AND social <= 64)
Foreign-key constraints:
"words_social_uid_fkey" FOREIGN KEY (uid) REFERENCES words_users(uid)
ON DELETE CASCADE
Referenced by:
TABLE "words_payments" CONSTRAINT "words_payments_sid_fkey" FOREIGN KEY
(sid, social) REFERENCES words_social(sid, social) ON DELETE CASCADE
# \d words_moves
Table "public.words_moves"
Column | Type | Collation | Nullable |
Default
---------+--------------------------+-----------+----------+------------------------------------------
mid | bigint | | not null |
nextval('words_moves_mid_seq'::regclass)
action | text | | not null |
gid | integer | | not null |
uid | integer | | not null |
played | timestamp with time zone | | not null |
tiles | jsonb | | |
score | integer | | |
letters | text | | |
Indexes:
"words_moves_pkey" PRIMARY KEY, btree (mid)
Check constraints:
"words_moves_score_check" CHECK (score >= 0)
Foreign-key constraints:
"words_moves_gid_fkey" FOREIGN KEY (gid) REFERENCES words_games(gid) ON
DELETE CASCADE
"words_moves_uid_fkey" FOREIGN KEY (uid) REFERENCES words_users(uid) ON
DELETE CASCADE
Referenced by:
TABLE "words_daily" CONSTRAINT "words_daily_mid_fkey" FOREIGN KEY (mid)
REFERENCES words_moves(mid) ON DELETE CASCADE
TABLE "words_scores" CONSTRAINT "words_scores_mid_fkey" FOREIGN KEY
(mid) REFERENCES words_moves(mid) ON DELETE CASCADE
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