Question

我正在尝试在PostgreSQL中创建一个滑动窗口，涉及一个while循环，但是我运行了此窗口：

CREATE OR REPLACE FUNCTION for_loop_through_query(sql text)
RETURNS TABLE (name text, rowcount integer) AS $$
declare
yyyymmddtrbeg varchar :='';
yyyymmddtrend varchar :='';
sql1 varchar := '';
sql3 varchar := '';
sql2 varchar :=

'SELECT m.id
FROM merchants AS m
WHERE t.server_time_created_at >= ''yyyymmddtrbeg'' and t.server_time_created_at <''<yyyymmddtrend>''))';

year int := 2019;
counter_mon int := 7;
counter_ttl int := 2;

begin 
while counter_ttl > 0 loop 
    while counter_mon <=12 and counter_ttl > 0 loop

         yyyymmddtrbeg  := (select cast(year as varchar(4)) + '-' + right('0' + cast (counter_mon as varchar(2)),2) + '-01');

         yyyymmddtrend := (select case when counter_mon in (11,12) then cast(year+1 as varchar(4)) else cast(year as varchar(4)) end
            + '-' + right('0' + case when counter_mon = 12 then '02' 
                                     when counter_mon = 11 then '01' else 
            right('0' + cast (counter_mon+2 as varchar(2)),2) end + '-01'));
         sql3 := sql2;
         sql3 := replace(sql3,'<yyyymmddtrbeg>',  yyyymmddtrbeg );
         sql3 := replace(sql3,'<yyyymmddtrend>',  yyyymmddtrend );
         sql1 := sql1 + sql3;
         counter_mon  := counter_mon + 1;
         counter_ttl := counter_ttl - 1;
         if counter_ttl <> 0 
            then sql1 := sql1 + ' union all ';
    end loop;
    counter_mon := 1; year  := year + 1;
end loop; exec (sql1);
end
$$ LANGUAGE plpgsql;

它会引发有关第一个结束循环的错误：

ERROR:  syntax error at or near "loop"
end loop;
      ^
SQL state: 42601

有人可以告诉我如何解决此问题吗？

PostgreSQL，SQL状态：42601-While循环

0 个答案: