feat(snowflake): Transpile exp.StrToDate (#4348)

Author: VaggelisD

sqlglot/dialects/snowflake.py

@@ -839,6 +839,7 @@ class Generator(generator.Generator):
             exp.StrPosition: lambda self, e: self.func(
                 "POSITION", e.args.get("substr"), e.this, e.args.get("position")
             ),
+            exp.StrToDate: lambda self, e: self.func("DATE", e.this, self.format_time(e)),
             exp.Stuff: rename_func("INSERT"),
             exp.TimeAdd: date_delta_sql("TIMEADD"),
             exp.Timestamp: no_timestamp_sql,

tests/dialects/test_bigquery.py

@@ -1517,6 +1517,14 @@ def test_bigquery(self):
                 "duckdb": "SELECT CAST(STRPTIME('Thursday Dec 25 2008', '%A %b %-d %Y') AS DATE)",
             },
         )
+        self.validate_all(
+            "SELECT PARSE_DATE('%Y%m%d', '20081225')",
+            write={
+                "bigquery": "SELECT PARSE_DATE('%Y%m%d', '20081225')",
+                "duckdb": "SELECT CAST(STRPTIME('20081225', '%Y%m%d') AS DATE)",
+                "snowflake": "SELECT DATE('20081225', 'yyyymmDD')",
+            },
+        )
         self.validate_all(
             "SELECT ARRAY_TO_STRING(['cake', 'pie', NULL], '--') AS text",
             write={