There are two columns with headings "new image Name" and "source image Name".  The new images are derived from source images. Also, occasionally, images are created from existing images as well. Please see sample data below.        new image Name | source image Name ---------------------------------- image1 | baseline image2 | baseline image3 | image1 image4 | baseline image5 | image3 image6 | imageX          Observations: From above table, we see that "image3" is derived from "image1" which is derived from "baseline".  For "image5" in col1, it is derived from "image3", which in turn is derived from "image1".  For "image6" in col1, it is derived from "imageX" which can be an "Unknown" source Requirements: Wherever we see that it is not "baseline" in col2, we need to check if corresponding value exists in col1 and populate its col2 value. If we get "baseline" as output, then we need to mark it "baseline" If we get another image name as the col2 value, then we need to mark it "Unknown" If we get an imageX as the col2 value, then we need to mark it "Unknown" Final result:       new image Name | source image Name ---------------------------------- image1 | baseline image2 | baseline image3 | baseline image4 | baseline image5 | Unknown image6 | Unknown         Please help. ... View more