如何在for循环中存储多列输出

列名称,总计数 abc 45 def 30 fgh 10

enter code here

CREATE OR REPLACE FUNCTION gtr_ops.f_column_validation()
RETURNS TABLE
(
column_name character varying(50),
total_blank_records bigint
 )
AS 
$BODY$
 DECLARE
 i record;
ecode CHARACTER VARYING(1000);
 vsql text;
 BEGIN
raise notice 'entering for loop';
for i IN (select column_name from information_schema.columns where table_schema='xyz'
and table_name='xyz')
LOOP
--RAISE NOTICE '%', i.column_name;
column_name := i.column_name;
vsql := 'select count(*) from schema.tablename
 where '|| i.column_name||' is null
group by '|| i.column_name;
RAISE NOTICE '%', vsql;
EXECUTE vsql into total_blank_records;
RETURN NEXT;
END LOOP;
 EXCEPTION
 WHEN OTHERS THEN
   ecode := SQLSTATE||' Error Message:'|| SQLERRM;
   raise notice 'Err Msg: %',ecode;
   END;
    $BODY$
    LANGUAGE plpgsql VOLATILE;

错误

需要指导来解决错误