MySQL greatest value in row?

Question

I\'m using MySQL with PHP. This is like my table: (I\'m using 3 values, but there are more)

id | 1 | 2 | 3
---+---+---+----
1  | 3 |12 |-29
2  | 5 |8  |8
3  | 99|7         


        

Answer 1

This is a great example of the way normalization helps make query design easier. In First Normal Form, you would create another table so all the values would be in one column, on separate rows.

Since you have used repeating groups to store your values across three columns, you can find the column with the greatest value this way:

SELECT id, IF(col1>col2 AND col1>col3, 'col1', IF(col2>col3, 'col2', 'col3')) 
  AS column_with_greatest_value
FROM mytable;