fix(presto): transpile FROM_ISO8601_DATE to cast [CLAUDE] (#7778)

FROM_ISO8601_DATE is a Presto/Trino function parsing an ISO 8601 string
into a date. It wasn't recognized as a dedicated expression, so it
parsed as Anonymous and passed through unchanged to all dialects. Add a
FromISO8601Date expression, transpile it to CAST(... AS DATE) in the base
Generator, and keep the native function for Presto/Trino.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Jo <46752250+georgesittas@users.noreply.github.com>

Author: 3 people

sqlglot/expressions/temporal.py

@@ -437,6 +437,10 @@ class FromISO8601Timestamp(Expression, Func):
     _sql_names = ["FROM_ISO8601_TIMESTAMP"]
 
 
+class FromISO8601Date(Expression, Func):
+    _sql_names = ["FROM_ISO8601_DATE"]
+
+
 class ParseDatetime(Expression, Func):
     arg_types = {"this": True, "format": False, "zone": False, "default_year": False}
 

sqlglot/generator.py

@@ -3991,6 +3991,9 @@ def fromtimezone_sql(self, expression: exp.FromTimeZone) -> str:
         zone = self.sql(expression, "zone")
         return f"{this} AT TIME ZONE {zone} AT TIME ZONE 'UTC'"
 
+    def fromiso8601date_sql(self, expression: exp.FromISO8601Date) -> str:
+        return self.sql(exp.cast(expression.this, exp.DType.DATE))
+
     def fromiso8601timestamp_sql(self, expression: exp.FromISO8601Timestamp) -> str:
         return self.sql(exp.cast(expression.this, exp.DType.TIMESTAMPTZ))
 

sqlglot/generators/presto.py

@@ -304,6 +304,7 @@ class PrestoGenerator(generator.Generator):
         exp.Encode: lambda self, e: encode_decode_sql(self, e, "TO_UTF8"),
         exp.FileFormatProperty: lambda self, e: f"format={self.sql(exp.Literal.string(e.name))}",
         exp.First: _first_last_sql,
+        exp.FromISO8601Date: rename_func("FROM_ISO8601_DATE"),
         exp.FromISO8601Timestamp: rename_func("FROM_ISO8601_TIMESTAMP"),
         exp.FromTimeZone: lambda self, e: (
             f"WITH_TIMEZONE({self.sql(e, 'this')}, {self.sql(e, 'zone')}) AT TIME ZONE 'UTC'"

tests/dialects/test_presto.py

@@ -45,6 +45,18 @@ def test_cast(self):
                 "bigquery": "SELECT CAST('2020-05-11T11:15:05' AS TIMESTAMP)",
             },
         )
+        self.validate_all(
+            "SELECT FROM_ISO8601_DATE('2020-05-11')",
+            write={
+                "duckdb": "SELECT CAST('2020-05-11' AS DATE)",
+                "presto": "SELECT FROM_ISO8601_DATE('2020-05-11')",
+                "trino": "SELECT FROM_ISO8601_DATE('2020-05-11')",
+                "snowflake": "SELECT CAST('2020-05-11' AS DATE)",
+                "spark": "SELECT CAST('2020-05-11' AS DATE)",
+                "databricks": "SELECT CAST('2020-05-11' AS DATE)",
+                "bigquery": "SELECT CAST('2020-05-11' AS DATE)",
+            },
+        )
         self.validate_all(
             "CAST(x AS INTERVAL YEAR TO MONTH)",
             write={