Implementing the basics of level of detail expressions

Level of detail (LOD) expressions are a very useful feature of Tableau. In order to understand what LOD expressions do, we must first understand what LOD is. When we use one dimension in our view, Tableau aggregates the measures along this dimension; so, we say that this dimension provides the LOD. If we add another dimension to the view, measures will be additionally disaggregated along this dimension as well, leading to an even more granular LOD. LOD expressions allow us to control the LOD that will be used in our view independently of the fields that are included in the view itself. We can make it either more or less granular than the LOD provided by the fields included in the visualization itself, which provides for flexibility in creating our views.

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