feat(duckdb): Add transpilation support for TRY_CAST#7672
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feat(duckdb): Add transpilation support for TRY_CAST#7672fivetran-amrutabhimsenayachit wants to merge 1 commit into
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SQLGlot Integration Test ResultsComparing:
By Dialect
Overallmain: 113247 total, 112163 passed (pass rate: 99.0%), sqlglot version: sqlglot:RD-1069322-try-cast: 110938 total, 110147 passed (pass rate: 99.3%), sqlglot version: Transitions: Dialect pair changes: 0 previous results not found, 1 current results not found ✅ 65 test(s) passed |
fivetran-amrutabhimsenayachit
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geooo109
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| return self.sql( | ||
| exp.case(exp.func("LOWER", src.copy())) | ||
| .when(exp.Literal.string("on"), exp.true()) | ||
| .when(exp.Literal.string("off"), exp.false()) | ||
| .else_(exp.TryCast(this=src.copy(), to=to)) | ||
| ) |
Collaborator
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Let's reuse _to_boolean_sql here.
| exp.cast( | ||
| exp.func("TRY_STRPTIME", src.copy(), exp.Literal.string(f)), "DATE" | ||
| ) | ||
| for f in self._TRYCAST_DATE_FORMATS |
Collaborator
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These are the only DATE_FORMATS that duckdb supports outside the ISO ?
| this=exp.TryCast(this=src.copy(), to=to), | ||
| expressions=[ | ||
| exp.func("TRY_STRPTIME", src.copy(), exp.Literal.string(f)) | ||
| for f in self._TRYCAST_TIMESTAMP_FORMATS |
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| src, to, to_type = expression.this, expression.to, expression.to.this | ||
|
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| # INTERVAL: TRY_CAST to INT first (preserves NULL for non-numeric input), then call to_*(). | ||
| if isinstance(to_type, exp.Interval): |
Collaborator
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Let's make something like:
if ...:
elif ...:
and lastly:
return super().trycast_sql(expression)
Collaborator
|
@fivetran-amrutabhimsenayachit let's break this PR into smaller ones, tackling the problem incrementally. |
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Snowflake's
TRY_CASTis semantically richer than DuckDB's: it usesAUTO date/timeformat detection (acceptingISO-8601, MM/DD/YYYY, and DD-Mon-YYYY), enforces string length constraints onCHAR(n)/VARCHAR(n), acceptsON/OFFas boolean values, and supports interval arithmetic. DuckDB's nativeTRY_CASThandles onlyISO-8601 dates, silently ignores length constraints, rejectsON/OFF, and has nostring-to-interval casting. A naive passthrough transpilation produces silently wrong results — not errors — making the gap invisible to users.This PR fixes it, except for the
NANOSECONDtime unit for which DuckDb has no support at all.