Question

我有一个rails应用程序，我试图从hstore中加总值。

这是查询：

# SELECT *, COALESCE(NULLIF(analytics->'2018.5.17.hits', '')::INT, 0) + COALESCE(NULLIF(analytics->'2018.5.18.hits', '')::INT, 0) + COALESCE(NULLIF(analytics->'20
18.5.19.hits', '')::INT, 0) + COALESCE(NULLIF(analytics->'2018.5.20.hits', '')::INT, 0) + COALESCE(NULLIF(analytics->'2018.5.21.hits', '')::INT, 0) + COALESCE(NULLIF(analyt
ics->'2018.5.22.hits', '')::INT, 0) + COALESCE(NULLIF(analytics->'2018.5.23.hits', '')::INT, 0) + COALESCE(NULLIF(analytics->'2018.5.24.hits', '')::INT, 0) as summed_hits F
ROM "searched_words" WHERE "searched_words"."account_id" = 2 AND (name ILIKE '%%') AND (analytics ?| ARRAY['2018.5.17.hits','2018.5.18.hits','2018.5.19.hits','2018.5.20.hit
s','2018.5.21.hits','2018.5.22.hits','2018.5.23.hits','2018.5.24.hits']) AND (summed_hits > 1) AND (analytics ?| ARRAY['2018.5.17.hits','2018.5.18.hits','2018.5.19.hits','2
018.5.20.hits','2018.5.21.hits','2018.5.22.hits','2018.5.23.hits','2018.5.24.hits']);
ERROR:  column "summed_hits" does not exist
LINE 1: ...22.hits','2018.5.23.hits','2018.5.24.hits']) AND (summed_hit...

我似乎无法理解，为什么postgres不能识别SELECT clouse中的summed_hits ......

谢谢！

Answer 1

您不能在其中使用别名，按照：

https://www.postgresql.org/docs/current/static/sql-select.html#SQL-SELECT-LIST

输出列的名称可用于引用列的值 ORDER BY和GROUP BY子句，但不在WHERE或HAVING子句中; 那里你必须写出表达式。

错误：列＆＃34; summed_hits＆＃34;不存在在选择中使用AS时

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