Support TRUNCATE IF EXISTS, STRUCT-field COLLATE, and Delta time travel#89
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Snowflake accepts an optional IF EXISTS clause in TRUNCATE [TABLE] [IF EXISTS] <name> (https://docs.snowflake.com/en/sql-reference/sql/truncate-table). Parse and round-trip it via a new if_exists flag on Statement::Truncate; previously the clause errored with "Expected end of statement, found: EXISTS".
Databricks permits a per-field COLLATE clause on string types in column, field, or variable type definitions, including fields nested inside STRUCT and ARRAY<STRUCT<...>> (https://docs.databricks.com/aws/en/sql/language-manual/sql-ref-collation). Consume the optional COLLATE name in the STRUCT field-definition parser; the collation carries no lineage so it is not retained in the AST. Fixes 2 corpus test failures (Databricks).
Support Delta Lake / Databricks time travel on table references: VERSION AS OF <version>, TIMESTAMP AS OF <expr>, and the @v<version> / @<yyyyMMddHHmmssSSS> shorthands, in both the pre-alias and post-alias positions (https://docs.databricks.com/aws/en/delta/history). The qualifier is captured on the AST via two new TableVersion variants (VersionAsOf, TimestampAsOf); the table name is unaffected so lineage is preserved. The @ shorthands canonicalize to the AS OF forms on display. Fixes 1 corpus test failure (Databricks).
Corpus Parsing ReportTotal: 191711 passed, 1920 failed (99.0% pass rate) ✨ No changes in test results By Dialect
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grasskode
approved these changes
Jun 18, 2026
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Three independent dialect parser fixes (one per commit), each with tests and verified against the corpus (0 regressions).
fix(snowflake): support TRUNCATE IF EXISTS— accept the optionalIF EXISTSclause inTRUNCATE [TABLE] [IF EXISTS] <name>(Snowflake docs). Captured via a newif_existsflag onStatement::Truncate.fix(databricks): accept COLLATE on STRING fields inside STRUCT— consume the per-fieldCOLLATE <name>clause on string types nested inSTRUCT<...>/ARRAY<STRUCT<...>>(collation docs). Collation carries no lineage so it is consumed but not retained. Fixes 2 corpus files.fix(databricks): parse Delta Lake time-travel qualifiers— supportVERSION AS OF <version>,TIMESTAMP AS OF <expr>, and the@v<version>/@<yyyyMMddHHmmssSSS>shorthands in both pre-alias and post-alias positions (time travel docs). Captured on the AST via two newTableVersionvariants. Fixes 1 real customer corpus file.All 1186 unit tests pass; corpus comparison shows 0 regressions.