Hi I had a question about creating a view by joining two tables in the data tab of a card.

Utz
Utz Member
in Cards, Dashboards, Stories

I am trying to join two tables to create a view in a DOMO card but I am running into a weird issue. Table 1 has 42.3 million rows and table 2 has 158K rows. When I do a left outer join to table 1 I am getting 297 million rows of data. Why am I getting more data than the two tables themselves it should be less data, not more.

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Answers

  • MichelleH
    MichelleH Coach

    @Utz Joins can return more rows than both tables combined if multiple matching rows are found between the two tables. In this case, it sounds like you want to return the same number of rows from your left table, but the same ItemNumbers appear multiple times in your right table.

    Without knowing the nuances of your specific datasets, I recommend figuring out how to make ItemNumber unique in your right table before joining (most likely in a dataflow). I also suggest reading the knowledge base article that explains how granularity affects joins: https://domo-support.domo.com/s/article/4405337525783?language=en_US#6.1.3

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