feat(snowflake)!: Transpilation support for STRIP_NULL_VALUE transpilation (tobymao#7403)

* feat(snowflake)!: Transpilation support for STRIP_NULL_VALUE transpilation.

* feat(snowflake)!: Transpilation support for STRIP_NULL_VALUE transpilation.

Author: fivetran-ashashankar

sqlglot/expressions/json.py

@@ -194,6 +194,10 @@ class JSONStripNulls(Expression, Func):
     _sql_names = ["JSON_STRIP_NULLS"]
 
 
+class StripNullValue(Expression, Func):
+    pass
+
+
 class JSONTable(Expression, Func):
     arg_types = {
         "this": True,

sqlglot/generators/duckdb.py

@@ -2551,6 +2551,13 @@ def parsejson_sql(self, expression: exp.ParseJSON) -> str:
             )
         return self.func("JSON", arg)
 
+    def stripnullvalue_sql(self, expression: exp.StripNullValue) -> str:
+        return self.sql(
+            exp.case()
+            .when(exp.func("json_type", expression.this).eq("NULL"), exp.null())
+            .else_(expression.this)
+        )
+
     @unsupported_args("decimals")
     def trunc_sql(self, expression: exp.Trunc) -> str:
         return self.func("TRUNC", expression.this)

tests/dialects/test_duckdb.py

@@ -327,6 +327,18 @@ def test_duckdb(self):
                 "snowflake": """SELECT GET_PATH(GET_PATH(PARSE_JSON('{"fruit": {"foo": "banana"}}'), 'fruit'), 'foo')""",
             },
         )
+        self.validate_all(
+            "CASE WHEN JSON_TYPE(x) = 'NULL' THEN NULL ELSE x END",
+            read={
+                "snowflake": "STRIP_NULL_VALUE(x)",
+            },
+        )
+        self.validate_all(
+            """SELECT CASE WHEN JSON_TYPE(JSON('{"a": null}') -> '$.a') = 'NULL' THEN NULL ELSE JSON('{"a": null}') -> '$.a' END""",
+            read={
+                "snowflake": """SELECT STRIP_NULL_VALUE(GET_PATH(PARSE_JSON('{"a": null}'), 'a'))""",
+            },
+        )
         self.validate_all(
             "SELECT {'bla': column1, 'foo': column2, 'bar': column3} AS data FROM source_table",
             read={