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。有没有办法做下面的事情？

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

您还可以使用update ... from语法并使用映射表。如果要更新多个列，则可以更通用：

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 fiddle demo

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;

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

遇到类似的情况，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;

报告-此处为表格，account_id与上述的report_ids相同。上面的查询将1条记录（符合条件的一条记录）设置为true，而所有不匹配的记录均设置为false。

要在单个查询中更新多行，可以尝试执行以下操作

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and此查询的一部分

假设您有一个ID数组和一个等效的状态数组-这是一个示例，该示例说明如何使用数组的静态SQL（由于值不同而不会改变的sql查询）：

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;