If you use the MIN function to find the lowest value in a range, any empty cell in that range will force the MIN function to return a zero. To find the minimum non-zero value in a range, you need to first create a calculation that will return either the non-zero value for each cell or a value that is higher than the non-zero minimum in the range.
Let's say you have numbers entered in A1 to A10. In B1, enter the following formula:
=IF(A1 = 0,MAX($A$1..$A$10),A1)
Plain English: If the value in A1 is zero, return the highest value from A1 to A10; if it is not zero, return the number. Once you have entered this, select cells B1 to B10 and fill down. Now you will have a column of numbers where the zeros (or empty cells) have been replaced by the highest number in column A. Now to find the minimum non-zero value in column A use this formula:
=MIN(B1..B10)
Since there are no zero values in column B, it will return the lowest number.
Note: Instead of MAX($A$1..$A$10), you could use any number that would be higher than the non-zero minimum, such as 10,000,000 or MAX($A$1..$A$10) -1.
Although ClarisImpact Tables have no visible cell references this solution will still work.