IF function not working

Anonymous 

If you are creating a measure then, this should

Measure  = 
if ( 
    MAX(table[Due Date]) = "null", "9999", MAX(table[Resolution Date]) - MAX(table[Due Date])
)

work.

So you are doing it in Power Query, this should work:

Table.AddColumn(#"Colonnes renommées13", "Major", each if [Priority] = "Major" and [Issue Type] = "Bug"  then 1 else 0)

Anonymous 

You can add as a column to your table using DAX:

Major = if ( and([Priority] = "Major" ,  [Issue Type] = "Bug" ) , 1 , 0)