Help with matrix in PBI

To do this, you will likely need to make a 2nd disconnected table of your column values (A..Z).  To get it to show in just one half of the matrix, you need some way to compare the row and column values, and use an IF along the line of = IF(MIN(Table1[Letter])<= MIN(Table2[Letter]), [Your Expression], "-")

Depending on what your expression is, you will likely need to use TREATAS() to pass the filter (column header value) from Table2 to Table1 for your calculation.

If your rows/columns are actual letters, that should work.  If not, you can have a Sort Order column on both and use that column in the MIN comparisons.

You can make the 2nd disconnected table with something like 

Table2 = DISTINCT(Table1[Letters])

Regards,

Pat