在PostgreSQL客户端psql中，可以使用df查看数据库搜索路径下的所有函数：
**postgres=# df** List of functions Schema | Name | Result data type | Argument data types | Type --------+-----------------------+--------------------+-------------------------- --------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- -------------------------------------------------------------------------+--------- public | __arima_adjust|double precision[]|distid integer, curr_tvals double precision[], prev_tvals double precision[], p integ er | normal public | __arima_diff
因为PostgreSQL中的函数有四种分类：aggregates/normal/trigger/window functions，所以psql中提供了附加参数，分别用来显示对应的函数：dfa、dfn、dft、dfw：
postgres=# dft List of functions Schema | Name | Result data type | Argument data types | Type --------+--------------------+------------------+---------------------+--------- public | checkauthtrigger | trigger | | trigger public | postgis_cache_bbox | trigger | | trigger (2 rows)
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