Question

来自postgres noob的问题。我在postgres有两张桌子。请参见下面的原理图。

strains_snps::table
    name::str
    variants_id::int array

variants::table
    id::int
    ref_base::str

我想

select variants_id 
from strains_snps 
where strains_snps.name = 'foo'

然后在后续查询中使用variants_id（这是一个int数组）。

select * 
from variants 
where id in the_output_from_previous_query

来自python，我会将第一个查询的输出分配给变量，然后在第二个查询中检查该变量的成员身份。但这可能不是最好的方式，我希望有一些方法可以让它作为单个查询工作？

修改

@Sumit建议使用子查询。我试过这个，但没有成功。

select * from variants 
where id in 
(select variants_id from strains_snps where name = 'BMD1964')

返回的错误pgadmin是

ERROR:  operator does not exist: integer = integer[]
LINE 2: where id in 
             ^
HINT:  No operator matches the given name and argument type(s). You  
might need to add explicit type casts.

********** Error **********

ERROR: operator does not exist: integer = integer[]
SQL state: 42883
Hint: No operator matches the given name and argument type(s). You might need to add explicit type casts.
Character: 34

Answer 1

试试这个：

select * 
from variants 
where id in (
    select unnest(variants_id) 
    from strains_snps 
    where strains_snps.name = 'foo' 
)

Answer 2

如果要使用WITH语句将其分隔：

WITH ids AS (
  SELECT UNNEST(variants_id) 
  FROM strains_snps
  WHERE strains_snps.name = 'foo' )
SELECT *
FROM variants
WHERE id IN (SELECT * FROM ids);

postgres选择从不同表中选择的数组中的id

2 个答案: