使用PostgreSQL在同一查询中更新多行

Question

我希望在一个语句中更新PostgreSQL中的多行。有没有办法做类似下面的事情？

UPDATE table 
SET 
 column_a = 1 where column_b = '123',
 column_a = 2 where column_b = '345'

Answer 1

您还可以使用update ... from语法并使用映射表。如果您想要更新多个列，则可以更加通用化：

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;

您可以根据需要添加任意数量的列：

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;

<强> sql fiddle demo

Answer 2

根据@Roman的解决方案，您可以设置多个值：

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', 'O\'Connell'),
  (2, 'robert@duncan.info', 'Robert', 'Duncan')
) as u2(id, email, first_name, last_name)
where u2.id = u.id;

Answer 3

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')

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

Answer 4

要在单个查询中更新多个行，可以尝试

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

如果您不需要其他条件，请删除此查询的 and 部分

Answer 5

遇到类似的情况，CASE表达对我很有用。

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

报告 - 此处是一个表格，account_id与上述report_ids相同。上面的查询将1个记录（匹配条件的记录）设置为true，将所有不匹配的记录设置为false。

Answer 6

假设您有一系列 ID 和状态的等效数组 - 以下是如何使用静态SQL执行此操作的示例（sql查询无法执行此操作）由于数组的不同值而改变：

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;

Answer 7

除了其他答案，评论和文档外，数据类型转换也可以按需使用。这样可以简化粘贴操作：

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;

Answer 8

我认为接受的答案并不完全正确。它取决于订单。这是一个无法与答案中的方法正确配合的示例。

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，有没有办法以顺序无关的方式来解决这个问题？

----尝试了几件事之后，这似乎与订单无关

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;

Answer 9

@Roman 感谢您的解决方案，对于任何使用 node 的人，我制作了这个实用方法来抽出查询字符串来更新 n 列的 n 条记录。

遗憾的是，它只处理具有相同列的 n 条记录，因此 recordRows 参数非常严格。

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;
}