sql - 在 PostgreSQL IF/THEN 语句中使用 DELETE FROM...RETURNING

Question

我有这个代码:

DO $$
returns table (msg varchar(500), isSuccessful BIT) as $BODY$
declare
newID integer := null;
id integer := 100;
BEGIN
IF newID is NULL 
then delete from table1 t1 where t1.id = id;
delete from table2 t2 where t2.id = id
returning 'test' as msg, 1 as isSuccessful;
else insert into table1(id, name)
values(id, 'testname');
END IF;
END $$; 

当我运行此程序时，我收到此错误:

错误:“返回”处或附近的语法错误

我本来没有returns table行，但经过一番研究后，我了解到我需要为 returning 中的数据建立一个表。要写入的行。

我想要返回的是以下内容:

<表类=“s-表”> <标题> 消息 成功 <正文> 测试 1

我的 returns table 做错了什么线以及如何实现我正在寻找的输出？另外，我是否必须创建一个函数才能使其工作？

Answer 1

示例如何将已删除的记录从表 sample1 插入到表 sample2 中:

with deleted_rows as (
    delete from test.sample1 where id = 123712
    returning id, first_name 
)
insert into test.sample2 (id, first_name) 
SELECT id, first_name from deleted_rows;

但是，如果您想获取这种格式的表格(msg，isSuccessful)，那么:

CREATE OR REPLACE FUNCTION test.delete_data(p_id integer)
RETURNS table (msg text, isSuccessful boolean)
LANGUAGE plpgsql
AS $function$
declare 
    deleted_id integer; 
begin

    delete from test.sample1 where id = p_id
    returning id into deleted_id;
    -- if this query does not delete any record, so variable "deleted_id" will be null

    if (deleted_id is not null) then 
        return query 
        select 'Success Deleted', true;
    else 
        return query 
        select 'No records deleted', false;
    end if;

end;
$function$
;