如何在PostgreSQL中获取聚合的定义/源代码？ [英] How to get definition/source code of an aggregate in PostgreSQL?

问题描述

我发现这个相关的答案很有用：

I found this related answer useful:

• 导出创建聚合 PostgreSQL中的函数

• Export "Create Aggregate" functions from PostgreSQL

但是我如何获得 CREATE AGGREGATE 没有GUI客户端的语句（例如，使用psql命令行）？

But how do I get the CREATE AGGREGATE statement without a GUI client (e.g. with psql command line)?

推荐答案

类似这样的事情，但是我不确定是否这涵盖了创建集合的所有可能方式（它绝对不会考虑使用引号引起的标识符）

Something like this, but I'm not sure if this covers all possible ways of creating an aggregate (it definitely does not take the need for quoted identifiers into account)

SELECT 'create aggregate '||n.nspname||'.'||p.proname||'('||format_type(a.aggtranstype, null)||') (sfunc = '||a.aggtransfn
       ||', stype = '||format_type(a.aggtranstype, null)
       ||case when op.oprname is null then '' else ', sortop = '||op.oprname end 
       ||case when a.agginitval is null then '' else ', initcond = '||a.agginitval end
       ||')' as source
FROM pg_proc p 
  JOIN pg_namespace n ON p.pronamespace = n.oid 
  JOIN pg_aggregate a ON a.aggfnoid = p.oid 
  LEFT JOIN pg_operator op ON op.oid = a.aggsortop 
where p.proname = 'your_aggregate'
  and n.nspname = 'public' --- replace with your schema name  

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