Q036error
Override names a missing column
An sgl.column in a query header names a column the query does not select.
db/queries/example.sql:2:15: error[Q036]: sgl.column references unknown output column "nickname"
Printed by sgl from a small PostgreSQL reproduction project.
When it is reported
Per-query overrides apply to output columns, so the name must appear in the SELECT list. The diagnostic suggests the closest output column.
How to fix it
Use the output column's name or alias.
See it in an example
In your terminal
$ sgl explain Q036
Look for UnknownOverrideColumn in Seagull's source to see where it is reported.