我想创建一个 postgres 存储过程或函数，从 2 个数据超过 30 天的表中删除数据

【问题标题】：I want to create a postgres stored procedure or function that deletes data from 2 tables where data is older than 30 days我想创建一个 postgres 存储过程或函数，从 2 个数据超过 30 天的表中删除数据
【发布时间】：2021-03-08 14:33:51
【问题描述】：

CREATE FUNCTION purge_data(integer) RETURNS int
   LANGUAGE plpgsql AS $$
DECLARE
   row_count int;
Begin
DELETE FROM table_a using table_b
 WHERE  table_a.session_id in (select table_b.id from table_b where cast (started as date) < current_date - ($1::text || '' days'')::interval);
IF found then 
   GET DIAGNOSTICS row_count = ROW_COUNT;
   RAISE NOTICE 'DELETED % row(s) FROM table_a', row_count;
END IF;
RETURN NULL;
END;
$$

我想返回从两个表中删除的行数。天数可能会改变，可能是 30 60 90

【问题讨论】：

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标签： sql postgresql plpgsql

【解决方案1】：

欢迎来到 SO。

如果我过于简单化了您的问题，请原谅我。但是DELETE 和RETURNING 不够吗？

数据样本

CREATE TEMPORARY TABLE t (id INT);
INSERT INTO t VALUES (generate_series(1,10));

查询

WITH j AS (
  DELETE FROM t WHERE id BETWEEN 1 AND 4
  RETURNING *
) SELECT count(*) FROM j;

 count 
-------
     4

演示：db<>fiddle

如果你必须将它放在 PL/pgSQL 函数中..

CREATE OR REPLACE FUNCTION purge_data(integer) RETURNS int LANGUAGE plpgsql AS $$
DECLARE row_count INT;
BEGIN
  WITH j AS (
    DELETE FROM t WHERE id BETWEEN 1 AND $1
    RETURNING *
) SELECT count(*) FROM j INTO row_count;
  RETURN row_count;
END;
$$;


SELECT purge_data(4);

 purge_data 
------------
      4

演示：db<>fiddle

【讨论】：