如何将插入查询返回的值分配给 PL/pgSQL 中的变量

我正在尝试在 Postgres 中创建一个执行简单插入的函数，并且我想要插入的 id 以供以后使用。但是我被说'Synatx error near (' at linequestion_key := INSERT INTO QUESTIONS(question, status, questionword) values (in_question, 'unanswered', in_questionword) RETURNING q_key;这是正确的分配方式吗？

CREATE OR REPLACE FUNCTION insert_new_record_hackathon(
    in_keywords character varying[],
    in_question text,
    in_questionword character varying)
  RETURNS void AS
$BODY$
DECLARE
i integer;
question_key integer;
keyword_key integer;
BEGIN
question_key := INSERT INTO QUESTIONS(question, status, questionword) values (in_question, 'unanswered', in_questionword) RETURNING q_key;

FOREACH i in ARRAY in_keywords
LOOP
keyword_key :=  INSERT INTO keywords(keyword) VALUES (in_keywords[i]) RETURNING k_key;
INSERT INTO qnkeywordmap(q_key, k_key) values (question_key, keyword_key)
END LOOP;

END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;