使用PostgreSQL更新同一查询中的多行

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'
225567 次浏览
小开

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')

和工作证明:http://sqlfiddle.com/ !2/97c7ea / 1

小开
最佳答案

你也可以使用update ... from语法和映射表。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;

< kbd > < a href = " http://sqlfiddle.com/ !12/2f536/1" rel="noreferrer">sql小提琴demo .

小开

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;
小开

假设你有一个数组id和等价的数组状态 -这里有一个例子，如何用一个静态SQL(一个SQL查询不会因为数组的不同值而改变)来做到这一点:

drop table if exists results_dummy;
create table results_dummy (id int, status text, created_at timestamp default now(), updated_at timestamp default now());
-- populate table with dummy rows
insert into results_dummy
(id, status)
select unnest(array[1,2,3,4,5]::int[]) as id, unnest(array['a','b','c','d','e']::text[]) as status;


select * from results_dummy;


-- THE update of multiple rows with/by different values
update results_dummy as rd
set    status=new.status, updated_at=now()
from (select unnest(array[1,2,5]::int[]) as id,unnest(array['a`','b`','e`']::text[]) as status) as new
where rd.id=new.id;


select * from results_dummy;


-- in code using **IDs** as first bind variable and **statuses** as the second bind variable:
update results_dummy as rd
set    status=new.status, updated_at=now()
from (select unnest(:1::int[]) as id,unnest(:2::text[]) as status) as new
where rd.id=new.id;
小开

遇到过类似的场景，CASE表达式对我很有用。

UPDATE reports SET is_default =
case
when report_id = 123 then true
when report_id != 123 then false
end
WHERE account_id = 321;

Reports -是这里的一个表，account_id与上面提到的report_ids相同。上面的查询将1条记录(符合条件的那条)设置为true，所有不匹配的记录设置为false。

小开

要在一个查询中更新多个行，您可以尝试这样做

UPDATE table_name
SET
column_1 = CASE WHEN any_column = value and any_column = value THEN column_1_value end,
column_2 = CASE WHEN any_column = value and any_column = value THEN column_2_value end,
column_3 = CASE WHEN any_column = value and any_column = value THEN column_3_value end,
.
.
.
column_n = CASE WHEN any_column = value and any_column = value THEN column_n_value end

如果不需要附加条件，则删除此查询的and部分

小开

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;
小开

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;
小开

@Roman感谢你的解决方案，对于任何使用节点的人来说，我使用这个实用工具方法来抽出一个查询字符串，用n条记录更新n列。

不幸的是，它只处理n个具有相同列的记录，所以recordRows参数是非常严格的。

const payload = {
rows: [
{
id: 1,
ext_id: 3
},
{
id: 2,
ext_id: 3
},
{
id: 3,
ext_id: 3
} ,
{
id: 4,
ext_id: 3
}
]
};


var result = updateMultiple('t', payload);


console.log(result);
/*
qstring returned is:


UPDATE t AS t SET id = c.id, ext_id = c.ext_id FROM (VALUES (1,3),(2,3),(3,3),(4,3)) AS c(id,ext_id) WHERE c.id = t.id
*/






function updateMultiple(table, recordRows){
var valueSets = new Array();
var cSet = new Set();
var columns = new Array();
for (const [key, value] of Object.entries(recordRows.rows)) {
var groupArray = new Array();
for ( const [key2, value2] of Object.entries(recordRows.rows[key])){
if(!cSet.has(key2)){
cSet.add(`${key2}`);
columns.push(key2);
}
groupArray.push(`${value2}`);
}
valueSets.push(`(${groupArray.toString()})`);
}
var valueSetsString = valueSets.join();
var setMappings = new String();
for(var i = 0; i < columns.length; i++){
var fieldSet = columns[i];
    

setMappings += `${fieldSet} = c.${fieldSet}`;
if(i < columns.length -1){
setMappings += ', ';
}
}
var qstring = `UPDATE ${table} AS t SET ${setMappings} FROM (VALUES ${valueSetsString}) AS c(${columns}) WHERE c.id = t.id`;
return qstring;
}

小开

@zero323提供的答案在Postgre 12上很有效。如果某人有column_b的多个值(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。


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