First, I hope I understand your setup correctly:
- You have several tables in SQL, some with tabular data and one table containing Lat/Long columns (probably floating/double precision data type).
- You would like to join several data tables together and see the information as points in ArcGIS.
Possible solution:
- You should make your join/view directly in SQL, joining data tables with the lat/long table. You will end up with a view that will have a.Col1, a.Col2, b.ColX, b.Lat, b.Long
- With the view created, you can add it to ArcMap using the Add XY Data dialog. It is accesible from File/Add XY Data.
- In the wizzard, select the view from the SQL database, add the Lat and Long columns to Y and X geometry columns.
- latitude is Y-axis, longitude is X-axis for WGS84, which is code EPSG:3844.
- the wizzard creates a new point Event Layer, which can be used in GIS analysis or saved as a distinct layer.
Problem with using query layer the way you presented:
Query Layers should be used only if joining geometry tables with data tables, to see the resulting query layer as a geometry in ArcMap. Since your are joining one data table to another, because the Lat/Long is not expressed as geometry (in a SQLGeometry data type) the query Layer will only add a table view in the Table of Contents. You can still use this table to create XY point event layer, similar to the steps described above.