Help with SQL statement: comparing multiple columns

Does somebody know if it’s possible with a single SQL statement to compare the values of multiple columns in one row of an MySQL database?

I want to select the lowest value from these columns.

I could do this with a loop within my PHP script, but this would mean that I need to do multiple database queries and each time compare the selected value with the previously selected value. However, preferrably I just want to do 1 query.

Cheers.