小编ana*_*arD的帖子

我需要以某种方式从 json 转换为 int。我已经做了这个功能：

CREATE OR REPLACE FUNCTION json2int(p_json json)
  RETURNS integer AS
$BODY$DECLARE
  v_json json;
  --v_char character varying;
  v_int integer;
BEGIN
  SELECT p_json->'additionalData'->'id' INTO v_json;
  --SELECT CAST(v_json as character varying) INTO v_char;
  SELECT CAST(v_json as integer) INTO v_int;
  RETURN v_int;
END;$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION json2int(json)
  OWNER TO postgres;

我尝试从 json 转换为 int，但没有用。然后我尝试从 json 转换为字符到 int，这也不起作用。所以我补充说：

CREATE CAST (json AS integer) WITH INOUT as implicit;

现在当我运行我的函数时：

SELECT json2int('{"additionalData":{"id":"4","userType":"viewer"},"type":"wall"}');

我收到此错误：

ERROR:  invalid input syntax for integer: ""4"" …