Question

如何用一句SQL查询不同条件的两列

select AVG(landsqmi) As LeftArea from spatial.us_states where ST_Xmax(geom)<-91.512817 and landsqmi>0;
select AVG(landsqmi) As RightArea from spatial.us_states where ST_XMin(geom)>-87.495491 and landsqmi>0;
这是我的两个要查询的列，这两个语句怎么合并成一句SQL？

Answer 1

select (
select AVG(landsqmi)  from spatial.us_states where ST_Xmax(geom)<-91.512817 and landsqmi>0 )As LeftArea,(
select AVG(landsqmi) from spatial.us_states where ST_XMin(geom)>-87.495491 and landsqmi>0)As RightArea

Answer 2

select
avg(case when ST_Xmax(geom)<-91.512817 and landsqmi>0 then landsqmi end) as LeftArea,
avg(case when ST_XMin(geom)>-87.495491 and landsqmi>0 then landsqmi end) as LeftArea
from
spatial.us_states

Answer 3

从表1一，表1 b，其中a.column1 =条件1和b.column2 =条件2选择A.1，B.1;