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Dicken's avatar
Dicken
Post Prodigy
2 years ago
Solved

Power Query Merge / expand and retain grouping / why is grouping Lost?

 Hi,    I sometimes find when I expand a table column after merging I lose grouping , in fact I cant even see a pattern, there must be one? ,  but If only need one colum I can aggregtte and expand a...
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  • lbendlin's avatar
    lbendlin
    2 years ago

    As always the caveat is that you have to validate for yourself which of the many ways to do lookups/joins/merges in Power Query is applicable in your scenario,  both from a performance and a scalability perspective. Thankfully we don't have to guess - we can use the query diagnostics to measure and know.

     

    As I said the best join is the one you don't do.

  • ronrsnfld's avatar
    ronrsnfld
    2 years ago

    What do you mean by "grouping"?

  • Anonymous's avatar
    Anonymous
    2 years ago

    Power Query merge operations do not guarantee the sort order after the merge, unless you buffer the table before the merge. Even if you sort them before the merge, the order may change. Power query does not like to bring the whole table in-memory, which it has to do with a sort operation.

     

    --Nate

Anonymous's avatar
Anonymous
Not applicable
2 years ago

Power Query merge operations do not guarantee the sort order after the merge, unless you buffer the table before the merge. Even if you sort them before the merge, the order may change. Power query does not like to bring the whole table in-memory, which it has to do with a sort operation.

 

--Nate