Question

你能在postgresql中做这样的事情吗？

select min(column1, column2) as Min, max(column1, column2) as Max from mytable;

Answer 1

您想使用LEAST（a，b）sql函数。

在另一个堆栈溢出问题How do I get the MIN() of two fields in Postgres?

上回答了这个问题

SELECT LEAST(column1, column2) as Min,
       GREATEST(column1, column2) as Max
FROM mytable;

官方postgresql文档是here。

Answer 2

选项1：

select CASE when a.min1 < a.min2 then a.min1 else a.min2 END as minimum,
CASE when a.max1 > a.max2 then a.max1 else a.max2 END as maximum
from (select min(col1) as min1, min(col2) as min2, max(col1) as max1, 
  max(col2) as max2 from myTable) a

选项2：

select CASE when MIN(col1) < MIN(col2) THEN MIN(col1) ELSE MIN(col2) END as Minimum,
  CASE WHEN MAX(col1) > MAX(col2) THEN MAX(col1) ELSE MAX(col2) END as Maximum
from myTable

最终选项：

select LEAST(MIN(col1),MIN(col2)) as myMinimum, GREATEST(MAX(col1),MAX(col2)) as myMaximum from myTable

这个怎么样？：）

Answer 3

select 
    min(CASE when a.min1 < a.min2 then a.min1 else a.min2 END) as minimum, 
    max(CASE when a.max1 > a.max2 then a.max1 else a.max2 END) as maximum 
from myTable as a

如何在postgresql中获取多个列的min？

3 个答案: