00627a7299
Drug filter WHERE clause used `drug_sequence IS NULL` to keep ancestor nodes, but levels 0-2 have empty string '' not NULL. Changed to level-based gating: - Drug filter: `(level < 3 OR drug_sequence LIKE ...)` - Directorate filter: `(level < 2 OR directory IN (...) OR directory IS NULL OR directory = '')` - Trust filter was already correct (had `OR trust_name = ''`)