[英]Update Redshift table from query
我正在尝试从查询更新 Redshift 中的表:
update mr_usage_au au
inner join(select mr.UserId,
date(mr.ActionDate) as ActionDate,
count(case when mr.EventId in (32) then mr.UserId end) as Moods,
count(case when mr.EventId in (33) then mr.UserId end) as Activities,
sum(case when mr.EventId in (10) then mr.Duration end) as Duration
from mr_session_log mr
where mr.EventTime >= current_date - interval '1 days' and mr.EventTime < current_date
Group By mr.UserId,
date(mr.ActionDate)) slog on slog.UserId=au.UserId
and slog.ActionDate=au.Date
set au.Moods = slog.Moods,
au.Activities=slog.Activities,
au.Durarion=slog.Duration
但我收到以下错误:
ERROR: syntax error at or near "au".
这对于 Redshift(或 Postgres)来说是完全无效的语法。 让我想起了 SQL Server ...
应该像这样工作(至少在当前的 Postgres 上):
UPDATE mr_usage_au
SET Moods = slog.Moods
, Activities = slog.Activities
, Durarion = slog.Duration
FROM (
select UserId
, ActionDate::date
, count(CASE WHEN EventId = 32 THEN UserId END) AS Moods
, count(CASE WHEN EventId = 33 THEN UserId END) AS Activities
, sum(CASE WHEN EventId = 10 THEN Duration END) AS Duration
FROM mr_session_log
WHERE EventTime >= current_date - 1 -- just subtract integer from a date
AND EventTime < current_date
GROUP BY UserId, ActionDate::date
) slog
WHERE slog.UserId = mr_usage_au.UserId
AND slog.ActionDate = mr_usage_au.Date;
Postgres 和 Redshift 通常就是这种情况:
FROM
子句加入附加表。SET
子句中对目标列进行表限定。此外, Redshift 是从很久以前的PostgreSQL 8.0.2 分叉出来的。 仅对 Postgres 应用了一些后来的更新。
UPDATE
语句中使用表别名- 这就是您看到的错误背后的原因。我简化了一些其他细节。
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