Get column name instead of column value

Question

My table table1 is like below

id   d1   d2   d3   d4
1    6    7    8    9
2    13   10   11   12
3    16   17   14   15
4    19   20   21   18
         


        

Answer 1

You can do this with a case expression:

SELECT d1, d2, d3, d4, least(d1, d2, d3, d4) as min_value,
       (CASE  least(d1, d2, d3, d4)
            WHEN d1 THEN 'd1'
            WHEN d2 THEN 'd2'
            WHEN d3 THEN 'd3'
            WHEN d4 THEN 'd4'
        END) as min_column_name
FROM table1;