How to fill column value of a matrix with specific color when there is no value in that specific cell?

Question

Hi All,
I need to create a 5/5  matrix in SSRS report. The data will be :
Col_Side   Col_Header   Col_data
1                  1                1
1                  1                 1
1                  2                1
1                  5                1
1                  5                1
1                  5                1
2                  3                1
2                  5                1
3                  1                2
3                  1                2
3                  1                2
4                   2               1
4                   4               1
5                   1               1
5                   1               1
5                   5               1
So, the matrix column will be Col_Header and matrix row will be Col_Side and count(Col_data) will be on the data.
Finally, it will create a 5 by 5 matrix with Count(Col_data) as its data for each combinations. If there is no combination (for ex: in the above data we do not have no combination of (1,3) , (1,4) , (2,1) etc..) then the matrix will be filling that corresponding
cell with zero.
Here I need to fill the cells with some colors based on some criteria.
I need to fill (5,3), (5,4), (5,5) combination with "Red" color.  Like this , I need to give different colors in each of the cells. Here, (5,5) combination will be having 1 in its cell.  (5,4) and (5,3) will be having zero in its corresponding
cells. I 'm trying to fill all the 3 cells with "Red" color. But, I am able to fill only (5,5) with "Red" color. Since the other 2 cells (5,3) and (5,4), has zero in their cells, it will not fill the cells with "Red" color. 
How can I fill those two cells (5,3) and (5,4) with red color?
I know this is very vague. I have no option to give the picture here..
Please suggest

Answer 1

Hi Julie,
According to your description, there is a 5/5 matrix with three fields: Col_Side, Col_Header, Col_data. You drag Col_Side field to Rows, Col_Header to Columns and Col_data to Data, then filling blank cells with zero using expression. Now you want to fill 
(5,3), (5,4), (5,5) cells with red color using expression, but it has no effect on cells (5,3) and (5,4).
According to my test, the expression has on effect on cells (5,3) and (5,4) since there is no corresponding data and the cells are blank. As a workaround, we can insert data for cells (5,3) and (5,4) in dataset, then use expression by following steps:
In the dataset, insert two sets of data (5,3,0), (5,4,0).
Right-click the cell of data, click Text Box Properties.
Click Fill in left pane, click (fx) button, then type the expression like below, then click OK.
=iif(Fields!Col_Side.Value=5 and Fields!Col_Header.Value >=3 ,"red","white" )
The following screenshot is for your reference:
If you have any more questions, please feel free to ask.
Thanks,
Wendy Fu