The following documentation comment has been logged on the website: Page: https://www.postgresql.org/docs/18/queries-union.html Description:
I'm very confused about this statement in the documentation of UNION: "UNION effectively appends the result of query2 to the result of query1". Because, if I append one item to a list, it is still the same list. But in the case of UNION, it's ""copied"" into a new anonymous derived-table. Alias don't work anymore, which I would expect if I just append some rows. Or is it like "effectively" means that this statement is not to be taken literally? In that case I would really appreciate a more detailed description, that after the UNION with tables a new anonymous derived-table is returned and the original first table can't be accessed anymore. Thank you for taking your time to read this even if you disagree.
