我希望在一条语句中更新PostgreSQL中的多行。有没有一种方法可以像下面这样做?
UPDATE table
SET
column_a = 1 where column_b = '123',
column_a = 2 where column_b = '345'
我希望在一条语句中更新PostgreSQL中的多行。有没有一种方法可以像下面这样做?
UPDATE table
SET
column_a = 1 where column_b = '123',
column_a = 2 where column_b = '345'
当前回答
是的,你可以:
UPDATE foobar SET column_a = CASE
WHEN column_b = '123' THEN 1
WHEN column_b = '345' THEN 2
END
WHERE column_b IN ('123','345')
并工作证明:http://sqlfiddle.com/#!2/97c7ea / 1
其他回答
你也可以使用update…从语法和使用映射表。如果你想要更新多个列,它是更一般化的:
update test as t set
column_a = c.column_a
from (values
('123', 1),
('345', 2)
) as c(column_b, column_a)
where c.column_b = t.column_b;
你可以添加任意多的列:
update test as t set
column_a = c.column_a,
column_c = c.column_c
from (values
('123', 1, '---'),
('345', 2, '+++')
) as c(column_b, column_a, column_c)
where c.column_b = t.column_b;
SQL演示
除了其他答案、注释和文档之外,数据类型转换还可以放在使用上。这允许更容易的复制粘贴:
update test as t set
column_a = c.column_a::number
from (values
('123', 1),
('345', 2)
) as c(column_b, column_a)
where t.column_b = c.column_b::text;
我认为公认的答案并不完全正确。它是顺序相关的。下面是一个用答案的方法不能正确工作的例子。
create table xxx (
id varchar(64),
is_enabled boolean
);
insert into xxx (id, is_enabled) values ('1',true);
insert into xxx (id, is_enabled) values ('2',true);
insert into xxx (id, is_enabled) values ('3',true);
UPDATE public.xxx AS pns
SET is_enabled = u.is_enabled
FROM (
VALUES
(
'3',
false
,
'1',
true
,
'2',
false
)
) AS u(id, is_enabled)
WHERE u.id = pns.id;
select * from xxx;
所以问题仍然存在,有没有一种独立于顺序的方法?
----在尝试了一些事情后,这似乎是独立的秩序
UPDATE public.xxx AS pns
SET is_enabled = u.is_enabled
FROM (
SELECT '3' as id, false as is_enabled UNION
SELECT '1' as id, true as is_enabled UNION
SELECT '2' as id, false as is_enabled
) as u
WHERE u.id = pns.id;
根据@Roman的解决方案,可以设置多个值:
update users as u set -- postgres FTW
email = u2.email,
first_name = u2.first_name,
last_name = u2.last_name
from (values
(1, 'hollis@weimann.biz', 'Hollis', 'Connell'),
(2, 'robert@duncan.info', 'Robert', 'Duncan')
) as u2(id, email, first_name, last_name)
where u2.id = u.id;
@zero323提供的答案在Postgre 12上很有效。如果有人对column_b有多个值(在OP的问题中引用)
UPDATE conupdate SET orientation_status = CASE
when id in (66934, 39) then 66
when id in (66938, 49) then 77
END
WHERE id IN (66934, 39, 66938, 49)
在上面的查询中,id类似于column_b;Orientation_status类似于问题的column_a。