feat(singlestore): Fixed parsing/generation of exp.JSONArrayAgg (#5819)

* feat(singlestore): Fixed parsing/generation of exp.JSONArrayAgg

* Fixed merge issues

Author: AdalbertMemSQL

sqlglot/dialects/mysql.py

@@ -691,7 +691,7 @@ def _parse_alter_table_alter_index(self) -> exp.AlterIndex:
     class Generator(generator.Generator):
         INTERVAL_ALLOWS_PLURAL_FORM = False
         LOCKING_READS_SUPPORTED = True
-        NULL_ORDERING_SUPPORTED = None
+        NULL_ORDERING_SUPPORTED: t.Optional[bool] = None
         JOIN_HINTS = False
         TABLE_HINTS = True
         DUPLICATE_KEY_UPDATE_WITH_SET = False

sqlglot/dialects/singlestore.py

@@ -205,6 +205,10 @@ class Parser(MySQL.Parser):
 
         FUNCTION_PARSERS: t.Dict[str, t.Callable] = {
             **MySQL.Parser.FUNCTION_PARSERS,
+            "JSON_AGG": lambda self: exp.JSONArrayAgg(
+                this=self._parse_term(),
+                order=self._parse_order(),
+            ),
         }
 
         NO_PAREN_FUNCTIONS = {
@@ -245,6 +249,7 @@ class Parser(MySQL.Parser):
 
     class Generator(MySQL.Generator):
         SUPPORTS_UESCAPE = False
+        NULL_ORDERING_SUPPORTED = True
         MATCH_AGAINST_TABLE_PREFIX = "TABLE "
 
         @staticmethod
@@ -368,6 +373,9 @@ def _unicode_substitute(m: re.Match[str]) -> str:
             exp.JSONPathSubscript: lambda self, e: self.json_path_part(e.this),
             exp.JSONPathRoot: lambda *_: "",
             exp.JSONFormat: unsupported_args("options", "is_json")(rename_func("JSON_PRETTY")),
+            exp.JSONArrayAgg: unsupported_args("null_handling", "return_type", "strict")(
+                lambda self, e: self.func("JSON_AGG", e.this, suffix=f"{self.sql(e, 'order')})")
+            ),
             exp.JSONArray: unsupported_args("null_handling", "return_type", "strict")(
                 rename_func("JSON_BUILD_ARRAY")
             ),

tests/dialects/test_singlestore.py

@@ -226,6 +226,15 @@ def test_json(self):
                 "": 'SELECT JSON_FORMAT(\'["G","alpha","20",10]\')',
             },
         )
+        self.validate_all(
+            "SELECT JSON_AGG(name ORDER BY id ASC NULLS LAST, name DESC NULLS FIRST) FROM t",
+            read={
+                "singlestore": "SELECT JSON_AGG(name ORDER BY id ASC NULLS LAST, name DESC NULLS FIRST) FROM t",
+                "oracle": "SELECT JSON_ARRAYAGG(name ORDER BY id ASC, name DESC) FROM t",
+            },
+        )
+        self.validate_identity("SELECT JSON_AGG(name) FROM t")
+        self.validate_identity("SELECT JSON_AGG(t.*) FROM t")
         self.validate_all(
             "SELECT JSON_BUILD_ARRAY(id, name) FROM t",
             read={