Question

我正在尝试按名称收集居住在用户指定州周围的州中的所有家庭。如下所示。但是，在执行代码时出现此错误，但不确定如何解决：

错误：

ERROR:  syntax error at or near "x"
LINE 13:  families WHERE state_name IN x.names and family_name...

代码：

with x as (
    SELECT 
        bordering_states_names as names
    FROM 
        states 
    WHERE 
        state_name = 'Ohio' 
)
SELECT 
    family_name,
    state_name
FROM 
    families WHERE state_name IN x.names and family_name IS NOT NULL
LIMIT 20

在这种情况下，bordering_states_names的值如下所示：

{"Ohio", "Indiana", "West Virginia", "Pennsylvania"}

Answer 1

您可以将其重写为：

with x as (
    SELECT bordering_states_names as names
    FROM states 
    WHERE state_name = 'Ohio' 
)
SELECT family_name,
       state_name
FROM families 
WHERE EXISTS (SELECT 1 FROM x WHERE state_name = ANY (names))
  AND family_name IS NOT NULL
LIMIT 20

Answer 2

对于以下查询，表x应该带有FROM part，否则x可能没有意义。

因此，联接这些表（families和x）可能是一种选择，如以下情况：

WITH x AS (
    SELECT 
        bordering_states_names as names
    FROM 
        states 
    WHERE 
        state_name = 'Ohio' 
)
SELECT f.family_name, f.state_name
  FROM families f inner join x
    ON ( f.state_name = x.names ) 
   AND family_name IS NOT NULL
 LIMIT 20;

将值传递给PostgreSQL中的子查询

2 个答案: