在PostgreSQL 10.6中，我试图将2个聚合函数调用的结果存储到avg_score表的avg_time和words_users列中，但是很遗憾出现语法错误：
WITH last_week_moves AS (
SELECT
m.gid,
m.uid,
m.played - LAG(m.played) OVER(PARTITION BY m.gid ORDER BY played) AS diff
FROM words_moves m
JOIN words_games g ON (m.gid = g.gid AND 5 IN (g.player1, g.player2))
WHERE m.played > CURRENT_TIMESTAMP - INTERVAL '1 week'
)
UPDATE words_users SET
avg_score = (SELECT ROUND(AVG(score), 1) FROM words_moves WHERE uid = 5),
avg_time = TO_CHAR(AVG(diff), 'HH24:MI')
FROM last_week_moves
WHERE uid = 5
GROUP BY uid;
（我在上面的语句中使用了硬编码的uid = 5，但在现实生活中，后者包裹在PL / PgSQL存储函数中，并使用了参数uid = in_uid）。
ERROR: 42601: syntax error at or near "GROUP"
LINE 15: GROUP BY uid
^
LOCATION: scanner_yyerror, scan.l:1128
数据库似乎对GROUP BY不满意，但我需要AVG(diff)使用它，因为CTE始终为游戏中的2位玩家提供两次移动之间的时间：
SELECT
m.gid,
m.uid,
m.played - LAG(m.played) OVER(PARTITION BY m.gid ORDER BY played) AS diff
FROM words_moves m
JOIN words_games g ON (m.gid = g.gid AND 5 IN (g.player1, g.player2))
WHERE m.played > CURRENT_TIMESTAMP - INTERVAL '1 week';
gid | uid | diff
-------+-------+-----------------------
50399 | 774 | ¤
50608 | 8977 | ¤
50608 | 5 | 00:39:48.121149
50608 | 8977 | 00:09:46.221235
50608 | 5 | 01:35:23.524209
50608 | 8977 | 09:26:40.794061
50697 | 5 | ¤
50697 | 10322 | 02:13:16.502079
50697 | 5 | 01:47:44.681788
50697 | 10322 | 00:01:31.597973
50697 | 5 | 12:11:24.54716
50697 | 10322 | 12:01:15.078243
50697 | 5 | 11:52:39.60056
50697 | 10322 | 00:11:30.491137
50697 | 5 | 00:14:53.612513
50697 | 10322 | 01:45:23.940957
...
52469 | 5 | 02:46:29.768655
52469 | 8550 | 01:16:45.169882
52469 | 5 | 08:38:00.691552
(59 rows)
请问有人知道如何更改我的UPDATE查询吗？
下面是有问题的3个表：
# \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 |
avg_score | double precision | | |
avg_time | text | | |
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
TABLE "words_stats" CONSTRAINT "words_stats_uid_fkey" FOREIGN KEY (uid) REFERENCES words_users(uid) 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 | | |
hand | text | | |
puzzle | boolean | | not null | false
Indexes:
"words_moves_pkey" PRIMARY KEY, btree (mid)
"words_moves_gid_played_idx" btree (gid, played DESC)
"words_moves_uid_idx" btree (uid)
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_scores" CONSTRAINT "words_scores_mid_fkey" FOREIGN KEY (mid) REFERENCES words_moves(mid) ON DELETE CASCADE
# \d words_games
Table "public.words_games"
Column | Type | Collation | Nullable | Default
----------+--------------------------+-----------+----------+------------------------------------------
gid | integer | | not null | nextval('words_games_gid_seq'::regclass)
created | timestamp with time zone | | not null |
finished | timestamp with time zone | | |
player1 | integer | | not null |
player2 | integer | | |
played1 | timestamp with time zone | | |
played2 | timestamp with time zone | | |
state1 | text | | |
state2 | text | | |
reason | text | | |
hint1 | text | | |
hint2 | text | | |
score1 | integer | | not null |
score2 | integer | | not null |
chat1 | integer | | not null |
chat2 | integer | | not null |
hand1 | character(1)[] | | not null |
hand2 | character(1)[] | | not null |
pile | character(1)[] | | not null |
letters | character(1)[] | | not null |
values | integer[] | | not null |
bid | integer | | not null |
friendly | boolean | | |
Indexes:
"words_games_pkey" PRIMARY KEY, btree (gid)
"words_games_player1_coalesce_idx" btree (player1, COALESCE(finished, 'infinity'::timestamp with time zone))
"words_games_player2_coalesce_idx" btree (player2, COALESCE(finished, 'infinity'::timestamp with time zone))
Check constraints:
"words_games_chat1_check" CHECK (chat1 >= 0)
"words_games_chat2_check" CHECK (chat2 >= 0)
"words_games_check" CHECK (player1 <> player2)
"words_games_score1_check" CHECK (score1 >= 0)
"words_games_score2_check" CHECK (score2 >= 0)
Foreign-key constraints:
"words_games_bid_fkey" FOREIGN KEY (bid) REFERENCES words_boards(bid) ON DELETE CASCADE
"words_games_player1_fkey" FOREIGN KEY (player1) REFERENCES words_users(uid) ON DELETE CASCADE
"words_games_player2_fkey" FOREIGN KEY (player2) REFERENCES words_users(uid) ON DELETE CASCADE
Referenced by:
TABLE "words_chat" CONSTRAINT "words_chat_gid_fkey" FOREIGN KEY (gid) REFERENCES words_games(gid) ON DELETE CASCADE
TABLE "words_moves" CONSTRAINT "words_moves_gid_fkey" FOREIGN KEY (gid) REFERENCES words_games(gid) ON DELETE CASCADE
TABLE "words_scores" CONSTRAINT "words_scores_gid_fkey" FOREIGN KEY (gid) REFERENCES words_games(gid) ON DELETE CASCADE
更新：
按照@lau的建议，我曾尝试将AVG移入CTE，但又遇到另一个语法错误：
WITH last_week_moves AS (
SELECT
m.gid,
m.uid,
TO_CHAR(AVG(m.played - LAG(m.played) OVER(PARTITION BY m.gid ORDER BY played)), 'HH24:MI') AS diff
FROM words_moves m
JOIN words_games g ON (m.gid = g.gid AND 5 IN (g.player1, g.player2))
WHERE m.played > CURRENT_TIMESTAMP - INTERVAL '1 week'
GROUP BY uid
)
UPDATE words_users SET
avg_score = (SELECT ROUND(AVG(score), 1) FROM words_moves WHERE uid = 5),
avg_time = diff
FROM last_week_moves
WHERE uid = 5;
ERROR: 42803: aggregate function calls cannot contain window function calls
LINE 5: TO_CHAR(AVG(m.played - LAG(m.played)...
^
LOCATION: check_agg_arguments_walker, parse_agg.c:728
答案 0 :(得分：1)
您似乎想要：
WITH last_week_moves AS (
SELECT m.uid,
(MAX(m.played) - MIN(m.played)) / NULLIF(COUNT(*) - 1, 0) as avg_diff,
AVG(score) as avg_score
FROM words_moves m JOIN
words_games g
ON m.gid = g.gid AND 5 IN (g.player1, g.player2)
WHERE m.played > CURRENT_TIMESTAMP - INTERVAL '1 week'
GROUP BY m.uid
)
UPDATE words_users wu
SET avg_score = lwm.avg_score,
avg_time = TO_CHAR(avg_diff, 'HH24:MI')
FROM last_week_moves lwm
WHERE wu.uid = lwm.uid AND
wu.uid = 5;
请注意，这简化了diff计算的计算，因此不需要lag()。
您可以看到这些是等效的： 值差异 1个 4 3 9 5
diff的平均值显然为4。这是((4 - 1) + (9 - 4)) / 2。您会看到“ 4”被取消，因此实际上是(9 - 1) / 2。这种观察是普遍的。