Sql postgres中的Sum列

我有一个varchar类型的列，值可以是任何字符串，是否可以找到可以转换为数值的所有行的总和

value
 ----
| 3  |
| 2 2|
| as |
| a1 |
| !2@|
| 0.5|
 ----
 3.5

您可以使用大小写表达式并转换：

select (case when value ~ '^[0-9]+[.]?[0-9]*$'
             then value::numeric
             else 0
        end)
from t;

是一个dbfiddle。

您可以使用大小写表达式并转换：

select (case when value ~ '^[0-9]+[.]?[0-9]*$'
             then value::numeric
             else 0
        end)
from t;

是一把小提琴。

可能是：

with tb as(

select '3' as v union all
select '2 2' as v union all
select 'as' as v union all
select 'a1' as v union all
select '!2' as v union all
select '0.5' 
)


select sum(case when v ~ '^[0-9\.]+$'
             then v::numeric
             else 0
        end) as result
from tb;

可能是：

with tb as(

select '3' as v union all
select '2 2' as v union all
select 'as' as v union all
select 'a1' as v union all
select '!2' as v union all
select '0.5' 
)


select sum(case when v ~ '^[0-9\.]+$'
             then v::numeric
             else 0
        end) as result
from tb;

---

你错过了总数。@TheImpler。我也忽略了0.5不是整数；你错过了总数。@TheImpler。我也忽略了0.5不是整数；