@JimmyJames: your example data and structure describes a vertical partition, not a lookup table. Whether it should be a lookup table (or even calculated column on the main table) is a separate issue. If it’s not a vertical partition, then you have not correctly conveyed the design of the table in your effort to obfuscate the source.
Even if the schema or table name make it explicit that this is supposed to be a lookup table, all that means is that the schema and/or name is misleading, it is vertical partitioning.
Discussion between JacquesB and Jimmy…
Discussion between JacquesB and Jimmy…