VAR and SWITCH Output issues

Hi Help_me 

The logic inside your SWITCH statement is actually perfectly structured. The reason your code is failing and skipping down to the individual mappings is due to a hidden DAX mechanic inside your HasA and HasB variables called Context Transition.

Because you are writing a Calculated Column, DAX evaluates the formula row by row (a Row Context). Whenever you use the CALCULATE function inside a Row Context, DAX performs a "context transition," which automatically converts the current row into a filter. This means CALCULATE silently applies a filter for every single column in that specific row. If the current row has an action of "B", DAX restricts the table to that specific row and then tries to apply your snapshot[action] = "A" filter. Because a row cannot be both "A" and "B" at the same time, COUNTROWS returns 0, meaning HasA evaluates to FALSE.

Try out this DAX

New Action = 
VAR CurrentProject = snapshot[project_Num]
VAR CurrentDate = snapshot[date]

VAR HasA =
    CALCULATE(
        COUNTROWS(snapshot),
        ALL(snapshot), -- Overrides context transition to scan the whole table
        snapshot[project_Num] = CurrentProject,
        snapshot[date] = CurrentDate,
        snapshot[action] = "A"
    ) > 0

VAR HasB =
    CALCULATE(
        COUNTROWS(snapshot),
        ALL(snapshot), -- Overrides context transition to scan the whole table
        snapshot[project_Num] = CurrentProject,
        snapshot[date] = CurrentDate,
        snapshot[action] = "B"
    ) > 0

RETURN
    SWITCH(
        TRUE(),
        
        -- If both A and B exist on same date for the same project
        snapshot[action] IN {"A","B"} && HasA && HasB, "Cheese/Crackers",
        
        -- Individual mappings
        snapshot[action] = "A", "Cheese",
        snapshot[action] = "B", "Crackers",
        snapshot[action] = "X", "Water",
        snapshot[action] = "Y", "Cookie",
        
        BLANK()
    )

If this solves your problem, please mark this as solved and give a kudos.
meso that i don't lose this thread.