Question

我正在使用触发器和函数将值插入另一个表中。

我有这张桌子 1）展

exhid   exhname             description    strtdate       enddate   status
101     The Famous          BLAH BLAH      2013-07-15   2013-10-13  SOON
102     York Exhibition     BLAH BLAH      2013-08-07   2014-01-19  End
103     Fine ART            BLAH BLAH      2014-09-26   2015-03-21  SOON

2）Works_Exhibitions

   alphid   numberid      exhid
    SCFI    1007          101
    SCBU    1008          101
    PAHF    1002          103
    PAHE    1003          103
    PASP    1004          103

和第三个空表，它与Works_Exhibitions具有相同的属性，并将其命名为Temp_works_exhibitions

alphid  numberid      exhid

我确实创建了这个功能并触发，所以一旦我将展览桌上的任何展览的状态更新为'结束'，我想将该展览的所有作品复制到新表Temp_works_exhibitions中然后删除它来自Works_exhibition表

CREATE OR REPLACE FUNCTION add2Temp_works_exhibitions() returns TRIGGER AS $updExhibStat$
BEGIN

IF(NEW.Status = 'End') THEN
INSERT INTO temp_works_exhibitions
select 

    Works_Exhibitions.alphID,
    Works_Exhibitions.numberID,
    Works_Exhibitions.exhID

from
    Works_Exhibitions
where
    Works_Exhibitions.exhID = (select Exhibitions.exhID from Exhibitions where  Exhibitions.Status = 'End');

delete from Works_Exhibitions where Works_Exhibitions.exhID = (select Exhibitions.exhID from Exhibitions where  Exhibitions.Status = 'End');

RETURN NEW;
END IF;
RETURN NULL;
END;

$updExhibStat$ LANGUAGE plpgsql;

--CREATE TRIGGER updExhibStat AFTER UPDATE ON Exhibitions FOR EACH ROW EXECUTE PROCEDURE add2Temp_works_exhibitions();

当我第一次测试时它确实有效但当我试图更新新的展览时我得到了这个错误

ERROR:  more than one row returned by a subquery used as an expression
CONTEXT:  SQL statement "INSERT INTO temp_works_exhibitions
select 

    Works_Exhibitions.alphID,
    Works_Exhibitions.numberID,
    Works_Exhibitions.exhID

from
    Works_Exhibitions
where
    Works_Exhibitions.exhID = (select Exhibitions.exhID from Exhibitions where  Exhibitions.Status = 'End')"
PL/pgSQL function add2temp_works_exhibitions() line 5 at SQL statement

任何想法如何解决此问题

Answer 1

我想我确实解决了这个问题

我确实在函数的末尾添加了这个命令

UPDATE Exhibitions set Status = 'Expired' where Exhibitions.Status = 'End';

我想这不是一个好的设计，但我没有其他解决方案

当我使用触发器时，子查询返回的Postgresql错误超过一行

1 个答案: