New column based on calculations between from same and others tables

[pvgadvogados]

I have 3 tables and I need to create a column in the last table with some conditions:

TABLE 1

Date Exchange	ID_EXCHANGE	Exchange Rates
25/04/2017	1	3,25
25/04/2017	2	3,30
26/04/2017	1	3,50
26/04/2017	2	3,12
27/04/2017	1	3,80
27/04/2017	2	3,19

TABLE 2

ID_EXCHANGE	ID_CURRENCY
1	U
2	E
3	R

TABLE 3

Date Sales	Value	ID_CURRENCY	NEW COLUMN - FINAL VALUE
26/04/2017	5000	U	17.500,00
26/04/2017	4000	E	12.480,00
26/04/2017	2000	R	2.000,00

A) The final value must be the result of the multiplication of the VALUE by the EXCHANGE RATE on the same day of the sale for that currency.

B) IF in table 3 the ID_CURRENCY is "R", the result of the new column (FINAL VALUE) will be the same as in the VALUE column.

Can you help me, please?

[v-yulgu-msft]

Hi @pvgadvogados,

You can refer to below formula to create a calculated column [Final Value] in Table3.

Final Value =
IF (
    Table3[ID_CURRENCY] = "R",
    Table3[Value],
    Table3[Value]
        * LOOKUPVALUE (
            Table1[Exchange Rates],
            Table1[ID_EXCHANGE], LOOKUPVALUE ( Table2[ID_EXCHANGE], Table2[ID_CURRENCY], Table3[ID_CURRENCY] ),
            Table1[Date Exchange], Table3[Date Sales]
        )
)

Best regards,
Yuliana Gu

[pvgadvogados]

Hi @v-yulgu-msft

LOOKUPVALUE is compatible with Direct Query?

I can't use... 

[v-yulgu-msft]

Hi @pvgadvogados,

Sorry, I don't know you were using Direct Query. LOOKUPVALUE is not a supported function in Direct Query mode.

In order to achieve your requirement, I think you can merge tables in Query Editor as suggested by dkay84 PowerBI.

At last, you only need to expand the merged table and remove some unnecessary columns.

Regards,
Yuliana Gu

[dkay84_PowerBI]

I'm sure a DAX ninja will solve this more elegantly than I have, but I used the query editor to do a few joins to get the appropriate exchange rate based on date and currency type, then added a custom column for the conditional math.

Here is the M code (for tables 1 just add the code after the "Source" or "Changed Type" line, as my data was hard coded based on your example):

// Table1
let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMtE3MtU3MjA0V9JRMgRiYz0jU6VYHVQJI7CEMUzcDFWDKYY4RL2hEUzCHFWDBYY4VIOlUmwsAA==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [#"Date Exchange" = _t, ID_Exchange = _t, #"Exchange Rates" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Date Exchange", type date}, {"ID_Exchange", Int64.Type}, {"Exchange Rates", type number}}),
    #"Merged Queries" = Table.NestedJoin(#"Changed Type",{"ID_Exchange"},Table2,{"ID_Exchange"},"NewColumn",JoinKind.LeftOuter),
    #"Expanded NewColumn" = Table.ExpandTableColumn(#"Merged Queries", "NewColumn", {"ID_Currency"}, {"ID_Currency"})
in
    #"Expanded NewColumn"


// Final Value
let
    Source = Table.NestedJoin(Table3,{"Date Sales", "ID_Currency"},Table1,{"Date Exchange", "ID_Currency"},"NewColumn",JoinKind.LeftOuter),
    #"Expanded NewColumn" = Table.ExpandTableColumn(Source, "NewColumn", {"Exchange Rates"}, {"Exchange Rates"}),
    #"Added Custom" = Table.AddColumn(#"Expanded NewColumn", "Final Value", each if [ID_Currency] <> "R" then [Value]*[Exchange Rates] else [Value])
in
    #"Added Custom"