Postgres 9.1中如何修复输入超出范围错误

Question

在Postgres 9.1下面的代码会产生错误

ERROR:  input is out of range
CONTEXT:  SQL function "gc_dist1" statement 1

如何在9.1中修复它？

create or replace function gc_dist1(_lat1 float8, _lon1 float8, _lat2 float8, _lon2 float8) 
returns float8 as $$ 
select ACOS(SIN(radians($1))*SIN(radians($3))+COS(radians($1))*COS(radians($3))*COS(radians($4)-radians($2)))*6371; 
$$ language sql immutable;

select gc_dist1(24.6269989013672,59.3357849157094,24.6269989013672,59.3357849121094);

Answer 1

如果失败，因为acos()函数不能接受高于1的值。 在你的例子中就是这种情况。

SELECT  (
        SIN(radians(24.6269989013672))
        * SIN(radians(24.6269989013672))
        + COS(radians(24.6269989013672))
        * COS(radians(24.6269989013672))
        * COS(radians(59.3357849121094)-radians(59.3357849157094))
    ) > 1 -- true

您的功能逻辑似乎不正确。