如何在具有 select 语句的 pgsql 函数中引用时间戳变量

Question

您好，我正在尝试编写一个 pgsql 函数，该函数将 table 数据复制到一个 csv 文件中，但在使用函数内部的变量值时遇到了困难，如下所示：

CREATE OR REPLACE  FUNCTION test3() RETURNS void
    LANGUAGE plpgsql
    AS $$
DECLARE
_currenttime timestamp := now();
BEGIN
copy (SELECT * FROM table1 WHERE createdtime < _currenttime - INTERVAL '1 days') TO '/tmp/table1.csv';
END
$$;

访问函数时出错：

select test3();

ERROR: column "_currenttime" does not exist LINE 1: ...py (SELECT * FROM table1 WHERE createdtime < _currentti... ^ QUERY: copy (SELECT * FROM bpminstance WHERE createdtime < _currenttime - INTERVAL '1 days') TO '/tmp/table1.csv'

请求您的帮助。

Answer 1

CREATE OR REPLACE  FUNCTION test3() RETURNS void
    LANGUAGE plpgsql
    AS $$
 DECLARE
_currenttime timestamp;
qry text;
BEGIN
_currenttime := NOW() - interval '1 day';
select 'copy (SELECT * FROM table1 WHERE createdtime < '''||_currenttime||''') TO ''/tmp/table1.csv''' into qry;
execute qry;
--codes
END
$$;

如何在具有 select 语句的 pgsql 函数中引用时间戳变量

how to refer timestamp variable in pgsql function having select statement

postgresql

sql-timestamp