Oracle Analytics supports cross-subject-area analyses , so the appropriate approach is to create the analysis using the primary subject area and then add another compatible or related subject area through the Analysis Editor.

Oracle's documented workflow starts by selecting one subject area and adding the initial analysis columns. The author then uses Add/Remove Subject Areas in the Subject Areas pane to include another subject area and select the additional required columns. Where local dimensions are involved, Oracle recommends including an appropriate measure from each participating subject area so that the semantic model can resolve the query correctly.

The Analysis Editor is therefore capable of querying multiple subject areas when the semantic relationships support the requested combination. Modifying the semantic model simply to expose every required column in one subject area is unnecessary when compatible subject areas already exist. UNION is a set operation used for combining compatible result sets and is not the standard mechanism for selecting related columns across subject areas. MERGE and dashboard prompts likewise do not establish semantic relationships.

Thus, the supported workflow is to create one analysis and add the second related subject area.

Reference Topic: Managing and Creating Analyses, Views, and Content — Cross-Subject-Area Analyses

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