Question

Can you do somwthing like this in postresql?

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

Answer 1

Option 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

Option 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

Final Option:

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

How about this one? 🙂