It is possible to break a view by removing a column from the table it depends on:

CREATE TABLE kv(k INT, v INT);
CREATE VIEW v1 AS SELECT k FROM (SELECT k,v FROM kv) AS t;
ALTER TABLE kv DROP COLUMN v;
SELECT * FROM v1; -- fails with `pq: column 2 does not exist`

The problem is that the view tracks dependencies based on "needed columns", which is a result of logical plan optimization. A column that is named by the query but not used by the view results becomes "unneeded" and is thus not tracked as dependency. When it is deleted from the source table, the view plan cannot be constructed any more.

cc @cockroachdb/sql-planning @cockroachdb/sql-async