sumproduct
 

I have a gantt chart that I want to calculate a couple of different things by
formula. Conditional formatting is already used in all cells. My formulas
is suppose to look at the row 1 of any given column Example Column O for any
data Like H for holiday and leave it blank if there is not data. Which this
formula works well by it's self. Since I have put this formula into place we
have needed another criteria. Which is....The second half of this formula is
suppose to look at Column J any row as defined which will be a date like
12-7-06 and if the Column the formula is in like column O matches O3 to
Column J's date then put what I have in column A in the column. Very
confusing and I am not sure if it will even work.
=SUMPRODUCT(ISBLANK(O$1),"",O$1)*(IF($J29=O3,$A$1) )