fix: correct json type mapping

duckdb_engine/__init__.py

@@ -159,6 +159,7 @@ class Dialect(PGDialect_psycopg2):
             # postgres type_codes (such as 701 for float) that duckdb doesn't have
             sqltypes.Numeric: sqltypes.Numeric,
             sqltypes.Interval: sqltypes.Interval,
+            sqltypes.JSON: sqltypes.JSON,
         },
     )
 

duckdb_engine/tests/test_datatypes.py

@@ -1,10 +1,11 @@
 from typing import Type
 
 from pytest import mark
-from sqlalchemy import Column, Integer
+from sqlalchemy import Column, Integer, select
 from sqlalchemy.engine import Engine
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import Session
+from sqlalchemy.types import JSON
 
 from ..datatypes import types
 
@@ -32,3 +33,22 @@ def test_unsigned_integer_type(
     session.commit()
 
     assert session.query(table).one()
+
+
+def test_json(engine: Engine, session: Session) -> None:
+    base = declarative_base()
+
+    class Entry(base):
+        __tablename__ = "test_json"
+
+        id = Column(Integer, primary_key=True, default=0)
+        meta = Column(JSON, nullable=False)
+
+    base.metadata.create_all(bind=engine)
+
+    session.add(Entry(meta={"hello": "world"}))  # type: ignore[call-arg]
+    session.commit()
+
+    result = session.scalar(select(Entry))
+
+    assert result.meta == {"hello": "world"}