feat(snowflake)!: provide transpilation support for HASH_AGG#7284
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fivetran-ashashankar wants to merge 2 commits intomainfrom
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feat(snowflake)!: provide transpilation support for HASH_AGG#7284fivetran-ashashankar wants to merge 2 commits intomainfrom
fivetran-ashashankar wants to merge 2 commits intomainfrom
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fivetran-ashashankar
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SQLGlot Integration Test ResultsComparing:
By Dialect
Overallmain: 4003 total, 4003 passed (pass rate: 100.0%), sqlglot version: sqlglot:RD-1069223-transpile_HASH_AGG: 4003 total, 4003 passed (pass rate: 100.0%), sqlglot version: Transitions: |
geooo109
reviewed
Mar 13, 2026
| bit_xor = exp.BitwiseXorAgg(this=hash_func) | ||
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| # Wrap with COALESCE(..., 0) | ||
| result = exp.Coalesce(this=bit_xor, expressions=[exp.Literal.number(0)]) |
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memory D SELECT HASH(NULL);
┌──────────────────────┐
│ hash(NULL) │
│ uint64 │
├──────────────────────┤
│ 13787848793156543929 │
└──────────────────────┘
HASH computes hash even for NULL. There is no need to apply COALESCE.
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| # HASH_AGG(col) -> COALESCE(BIT_XOR(HASH(col)), 0) | ||
| # HASH_AGG(col1, col2) -> COALESCE(BIT_XOR(HASH((col1, col2))), 0) | ||
| # HASH_AGG(DISTINCT col) -> COALESCE(BIT_XOR(DISTINCT HASH(col)), 0) | ||
| # HASH_AGG(*) -> COALESCE(BIT_XOR(HASH(*)), 0) |
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What happens if the we use as a winodw function ?
| self.validate_all( | ||
| "SELECT HASH_AGG(DISTINCT col1)", | ||
| write={ | ||
| "duckdb": "SELECT COALESCE(BIT_XOR(DISTINCT HASH(col1)), 0)", |
Collaborator
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This is not the correct approach here. We apply the DISTINCT on the HASH result right ? and not on the column.
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| if isinstance(cols[0], exp.Star): | ||
| # HASH(*) is not supported in DuckDB - HASH() requires explicit columns | ||
| # Generate a warning and use a placeholder | ||
| self.unsupported( | ||
| "HASH_AGG(*) cannot be fully transpiled to DuckDB. " | ||
| "DuckDB's HASH() function requires explicit columns, not *. " | ||
| "Please rewrite as HASH_AGG(col1, col2, ...) with specific columns." | ||
| ) | ||
| # Fall back to using Star - will cause runtime error but preserves intent | ||
| hash_arg = exp.Star() |
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This isn't complete, you can do:
memory D with t as (select 1 as a, 2 as b) select hash(unpack(columns(t.*))) from t;
┌──────────────────────────┐
│ hash(a := t.a, b := t.b) │
│ uint64 │
├──────────────────────────┤
│ 6530802887144669425 │
│ (6.53 quintillion) │
└──────────────────────────┘
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