previous month Revenue to the Current month

[RanjanThammaiah]

HI All,

I require assistance in ensuring that my DAX formula accurately calculates the Revenue for the previous month in comparison to the current month using a list of month names and revenue.

Month	Revenue	Previous Month Revenue
Jan	100
Feb	200	100
Mar	300	200
Apr	400	300
May	500	400
Jun	600	500
Jul	700	600
Aug	800	700
Sep	900	800
Oct	1000	900
Nov	1100	1000
Dec	1200	1100

I have created 2 DAX to convert the Text to values. When i was getting the error saying 

couldn't load the data for this visual MdxSctript(Model) (65,42) Calculation error in measure 'core Event Reason List'[Previous Month Revenue]; Cannot convert value 'Sep' of type text to type number.

1.Create a new table to map text month names to numeric values.

MonthMappingTable =
SUMMARIZE(
'Core Event Reason List',
'Core Event Reason List'[Fiscal Month],
"MonthNumber", SWITCH('Core Event Reason List'[Fiscal Month],
"Jan", 1,
"Feb", 2,
"Mar", 3,
"Apr", 4,
"May", 5,
"Jun", 6,
"Jul", 7,
"Aug", 8,
"Sep", 9,
"Oct", 10,
"Nov", 11,
"Dec", 12,
BLANK()
)
)

2.Create the 'Previous Month Revenue' measure using the mapping table.

Previous Month Revenue =

VAR CurrentMonth = MAX('Core Event Reason List'[Fiscal Month])

VAR PreviousMont=

    CALCULATE(

        MAX('Core Event Reason List'[Fiscal Month]),

        FILTER(ALL('Core Event Reason List'), 'Core Event Reason List'[Fiscal Month] < CurrentMonth)

    )

VAR PreviousMonthRevenue =

    CALCULATE(

        SUM('Weekly People Flash'[FTE WFP]) +

        [FTE for Return to Work] +

        [FTE for Leave of Absence] -

        [FTE for Termination],

        'Core Event Reason List'[Fiscal Month] = PreviousMont

    )

RETURN PreviousMonthRevenue

3. This isn't working.

Kindly provide if there are any possible solution.

[isjoycewang]

Hi @RanjanThammaiah,

Please see attached Exercise File. Feel free to let me know more about your table if any questions.

Try below measure:

Previous Month Revenue = 
VAR CurrentMonth = MAX('MonthMappingTable'[MonthNumber])
VAR PreviousMont=
    CALCULATE(
        MAX('MonthMappingTable'[MonthNumber]),
        FILTER(ALL('MonthMappingTable'), 'MonthMappingTable'[MonthNumber] < CurrentMonth)
    )
VAR PreviousMonthRevenue =
    CALCULATE(
        SUM('Core Event Reason List'[Revenue]), 
        ALL(MonthMappingTable[Fiscal Month]), MonthMappingTable[MonthNumber] = PreviousMont)
    
RETURN PreviousMonthRevenue

[DataNinja777]

Hi @RanjanThammaiah 

It is better that you create a separate calendar table (dimension table) to take advantage of the time intelligence functions which dax has to offer.  It is always recommended to create a data model with star schema with relationships between fact and dimension tables instead of trying to deal everything through your fact table. You can create a calender table by writing a dax formula like below and create a relationship with your fact table date field.  

Calendar =
CALENDAR ( MIN ( 'Fact table'[Date] ), MAX ( 'Fact table'[Date] ) )