Function checking blank position is not working

Question

I need to create measure that compares Currency from different tables. Simple if one column is empty then take data from other.

Material

Material no	Name
1234	Mat 1
5678	Mat 2
1290	Mat 3

Budget

Material no	Currency
1234	USD
5678
1290	EUR

JIRA

Material no	Currency
1234
5678	EUR
1290	EUR

Expected result

Material no	Currency
1234	USD
5678	EUR
1290	EUR

I've created measure

Miara-test = 
VAR Purchase_filter = MAXX('Budget','Budget'[Currency]) 
RETURN IF( ISBLANK(Purchase_filter)) || Purchase_filter = "", MAXX(JIRA,JIRA[Currency]), MAXX('Budget','Budget'[Currency]))

Due to whatever reason, I've received table that returns only currency in case they're same in both source data

Material no	Currency
1234
5678
1290	EUR

Answer 1

Try this Measure:

Currency_Measure = 

VAR BudgetCurrency = MINX(Budget, [Currency]) //since there is a relationship from Material to Budget, this gets the related value.
VAR JiraCurrency = MINX(JIRA, [Currency]) //gets related value

RETURN SWITCH(TRUE()
        , BudgetCurrency = BLANK(), JiraCurrency
        , JiraCurrency = BLANK(), BudgetCurrency
        , JiraCurrency = BudgetCurrency, JiraCurrency //doesn't matter which one we output
        , "" //if they both have data but are different, output blank for now
)

Example Output:

Material 1111 is an example where both the Currencies are different nonblank values.

Data Model:

The Material table is related to both Budget and Jira but the Material no column.