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crispybc
Frequent Visitor

Lookup MAX value from other table using power query

I have 2 tables.

One is a table of all timestamps per ID where a change has occured. [Lookup]

The other is high resolution timestamp table (30 min intervals) between the start and end dates of an ID. [History]

 

I have a solution in DAX where I lookup  the last change in [Lookup] for each value of [History]

 

 

LAST CHANGE = CALCULATE(MAXX(LOOKUP, LOOKUP[UPDATED_AT]), FILTER(LOOKUP,LOOKUP[ID] = HISTORY[ID] && LOOKUP[UPDATED_AT] <= HISTORY[Time Active]))

 

 

 

 

This works fine, until the datset grows too large (around 50 mil rows) . Then there is not enough memory to perform the DAX  calculation. I'm wondering if I can achieve the same within power query which is maybe not so memory hungry

1 REPLY 1
some_bih
Super User
Super User

Hi @crispybc  try using variable and see results

If this post helps, please consider accept as solution to help other members find it more quickly.

Test LAST CHANGE=
VAR _filteredtable =
FILTER(LOOKUP,LOOKUP[ID] = HISTORY[ID] && LOOKUP[UPDATED_AT] <= HISTORY[Time Active])
VAR _result=
CALCULATE(MAXX(LOOKUP, LOOKUP[UPDATED_AT]),
_filteredtable
)
RETURN
_result





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