How this Dax is working ?

[Anonymous]

Hi,

I don't have experience with DAX and I'm trying to understand a DAX which is used in a workbook.

Here is the link to workbook. https://community.tableau.com/servlet/JiveServlet/download/847360-289331/SampleData.xlsx


This is the formula which is used to calculate earned exposure.

=SUMX (
SUMMARIZE (
Table2,
Table2[InceptionDate],
Table2[ExpiryDate],
"Earned Exposure",
COUNTA(Table2[Policy Name])
* COUNTROWS (
CALCULATETABLE ('Table1',
KEEPFILTERS(
DATESBETWEEN (
Table1[DateKey],Table2[InceptionDate], Table2[ExpiryDate]
)
)
)
)
/ COUNTROWS (
DATESBETWEEN (
Table1[DateKey],Table2[InceptionDate], Table2[ExpiryDate]

)
)
),
[Earned Exposure]
)

Please help me to understand how earned exposure is calculated in Sheet1 for each month using above formulae.

Month	Earned Exposure
1	0.855191257
2	0.765027322
3	0.846994536

Regards,
Ombir

[v-shex-msft · Accepted solution]

Hi @Anonymous,

Description of formula segmentation:

SUMMARIZE ( Table2, Table2[InceptionDate], Table2[ExpiryDate],"Earned Exposure",expressions)

Summarize table based on two date columns and add custom column with following expressions.

COUNTA(Table2[Policy Name])

Calculate related 'policy name' count based on summarize columns.

COUNTROWS (CALCULATETABLE ('Table1',KEEPFILTERS (DATESBETWEEN ( Table1[DateKey], Table2[InceptionDate], Table2[ExpiryDate] ))))

 Filtered table1 row count based condition 'datekey' field in date range which defined by current row 'InceptionDate' and 'ExpiryDatefunction'.

COUNTROWS ( DATESBETWEEN ( Table1[DateKey], Table2[InceptionDate], Table2[ExpiryDate] ) )

Filtered datekey fields count in current date range.

SUMX (SummarizeTable,[Earned Exposure])

Get summarize of new column based on category fields in table visual.

Regards,

Xiaoxin Sheng