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azure-cosmosdbazure-cosmosdb-sqlapi

Issue with join in Azure Data Factory

I have created a simple ADF pipeline that has two sources (S1, S2) and stores data from these sources into Azure Cosmos DB sink using left outer join (condition: s1.abc = S2.abc). After running this pipeline, I can see all columns from S1 and none of the columns from S2. Why is that? Please help me understand.

Solution

  • I can see all columns from S1 and none of the columns from S2

    Since you mentioned left outer join in your question, so i think you are using Data Flow Activity to transfer the data. I tested on my side an it works for me.

    Firstly,please check the statement of left outer join in the official document:

    enter image description here

    Then please refer to my sample test:

    I have 2 csv files as below:

    enter image description here

    enter image description here

    My data flow activity as below, the B is the join key:

    enter image description here

    Output in cosmos db,the row from left stream has no match,so the output from right stream is NULL:

    enter image description here