Some databases support literals of the various GEO type, for example in Postgres, you can do:

SELECT POINT '1,1';

And in Postgres it enforces the sub-type at the column level:

SELECT POINT '1,1' UNION ALL SELECT LINE '0,0,1,1';

ERROR: UNION could not convert type line to point

However, some databases allow using various GEO types in the same column (such as BigQuery, as one example).

1. Is it possible to use the GEO|GEOMETRY|GEOGRAPHY keyword itself for literal creation, for example something like SELECT GEO '1,1' FROM tbl ?
2. Is it possible to have a GEO column that supports any sub-type within it?

CodePudding user response：

The following code seems to do the job.
Having said that, the fact that we can do something doesn't necessarily mean we should do it.

A similar post states:

"Client applications usually deny the work with a single generic geometry type column as well as multiple geometry columns in one table!"

          select 'POINT(1 1)'::geography(geometry)
union all select 'LINESTRING(0 0,1 1)'::geography(geometry)

Fiddle