Urgent: Formular question: get first/last month value with qty value

We've got a query result as the following:

Jan_2007 -- Feb_2007 -- Mar_2007 -- Apr_2007

0 --- 54 --- 0 --- 3

23 ---0 --- 12 --- 7

In the above query result,

1st row shows the sales quantity in Jan_2007 is 0, in Feb_2007 is 54, in Mar_2007 is 0, and in Apr_2007 is 3.

2nd row shows the sales quantity in Jan_2007 is 23, in Feb_2007 is 0, in Mar_2007 is 12, and in Apr_2007 is 7.

We would like to add a new column to get the first/last month value with quantity, e.g., in 1st row, the 1st month value with quantity value (>0) is Feb_2007, and the last month value with quantity value (>0) is Apr_2007. Therefore the 1st month value with qty is Feb_2007 and the last month value with qty is Apr_2007. In 2nd row, the first month value with qty is Jan_2007 and the last month value with qty is Apr_2007. But how to use formular to get the 1st/last month values with qty?

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