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

Question

我有这个代码：

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

当我运行这个时，我得到这个错误：

错误：“returns”处或附近的语法错误

我本来是没有returns table这一行的，但经过一番研究，我的理解是我需要为returning这一行的数据建立一个table来写入进入.

我想要return的是：

msg	isSuccessful
test	1

我的 returns table 行有什么问题？如何获得我正在寻找的输出？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 table sample1 中删除的记录插入 table sample2:

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，如果你想获得 table 这种格式 (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;
$function$
;

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

Using DELETE FROM...RETURNING in a PostgreSQL IF / THEN Statement

sql

postgresql

function

if-statement

sql-delete