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Follow-up to #352: UNNEST(...) alias, alias.field still reported as a table #689
Description
#352 (PR #617) fixed the simple case. Confirmed on 3.0.1:
Parser("SELECT A, B, metrics.C FROM tbl, UNNEST(metrics) as metrics").tables
# ['tbl'] ✅Flattening a repeated field off an alias bound by an earlier UNNEST still reports it as a table:
Parser("SELECT h.value FROM `proj.ds.ga_sessions_*` t, UNNEST(t.hits) h, h.customDimensions cd").tables
# ['proj.ds.ga_sessions_*', 'h.customDimensions'] ← expected ['proj.ds.ga_sessions_*']
# tables_aliases == {'t': 'proj.ds.ga_sessions_*', 'cd': 'h.customDimensions'} ← 'h' missingh is bound by the UNNEST and never appears in tables_aliases, so a consumer cannot tell a table from a flattened field. This is the standard BigQuery ga_sessions shape.
Activity
Yuren0312 commentedon Oct 18, 2026
Thanks for the clear repro — I can confirm this on current master. The root cause is that sqlglot parses a later
alias.fieldreference (e.g.h.customDimensionsafterUNNEST(t.hits) h) as anexp.Tablenode withdb=h, soTableExtractoremitsh.customDimensionsas a table name and the UNNEST aliashis never tracked.I've opened #702 with a minimal fix:
TableExtractornow collects the aliases introduced byexp.Unnestnodes (bothTableAlias.thisforUNNEST(x) AS aandTableAlias.columnsforUNNEST(x) a) and drops any table whose catalog/db segment matches one of them. The reported query now yieldstables == ['proj.ds.ga_sessions_*']andtables_aliases == {'t': 'proj.ds.ga_sessions_*'}.A regression test is included;
pytest test/is 277 passed with 100% coverage,mypyandruff checkare clean. Happy to adjust if you'd prefer a different approach.