pg 判断表或者模式是否存在 满足条件后执行创建表sql

create or replace function create_view_a() returns void as $$ declare viewExist integer;
begin
        select count(1) into viewExist FROM pg_namespace WHERE nspname = 'basedata'; --判断条件，可自己定义其他条件
	if viewExist != 0 then
			execute
			'CREATE VIEW view_a  AS
			SELECT
			aaa,bbb,ccc
			FROM  basedata.table_a;';
	 end if;
end;
$$ language plpgsql;
SELECT create_view_a()