Thank you! Something like ``` with t as ( select set_config('ns.blah', '1', false) as res ) select res from t; select current_setting('ns.blah'); ``` works for me. Andrew Gierth <andrew@xxxxxxxxxxxxxxxxxxxx> 于2019年1月4日周五 下午6:27写道: > > >>>>> "Zexuan" == Zexuan Luo <spacewanderlzx@xxxxxxxxx> writes: > > Zexuan> For instance: > Zexuan> ``` > Zexuan> with t as ( > Zexuan> select set_config('blah', '1', false) > Zexuan> ) > Zexuan> select current_setting('blah'); > > A CTE containing a SELECT query which is not referenced anywhere will > not be executed, even if it contains volatile functions. (CTEs > containing INSERT/UPDATE/DELETE that are not referenced _will_ still be > executed.) > > -- > Andrew (irc:RhodiumToad)