diff --git a/alembic/versions/cps_v2_platforms.py b/alembic/versions/cps_v2_platforms.py
index e80c1a6..75b53a1 100644
--- a/alembic/versions/cps_v2_platforms.py
+++ b/alembic/versions/cps_v2_platforms.py
@@ -28,34 +28,48 @@ def upgrade() -> None:
     op.add_column("cps_activity", sa.Column("payload", sa.Text(), nullable=True))
 
     # 群:多平台(现有群都是美团,server_default 回填)+ sid 可空
-    op.add_column(
-        "cps_group",
-        sa.Column(
-            "platforms",
-            sa.JSON().with_variant(postgresql.JSONB(), "postgresql"),
-            nullable=False,
-            server_default=sa.text("'[\"meituan\"]'::jsonb"),
-        ),
+    # server_default 按方言区分:Postgres 用 ::jsonb 转换;SQLite(本地)用纯 JSON 文本字面量
+    #(SQLite 不认 ::jsonb,会报 unrecognized token: ":")。
+    bind = op.get_bind()
+    platforms_default = (
+        sa.text("'[\"meituan\"]'::jsonb")
+        if bind.dialect.name == "postgresql"
+        else sa.text("'[\"meituan\"]'")
     )
-    op.alter_column("cps_group", "sid", existing_type=sa.String(64), nullable=True)
+    # alter_column 在 SQLite 原生不支持 ALTER COLUMN,必须走 batch(重建表);Postgres 下 batch 直接 ALTER。
+    # 用 batch_alter_table 跨方言通吃(render_as_batch 只管 autogenerate 渲染,不会自动包裹手写的 alter_column)。
+    with op.batch_alter_table("cps_group") as batch_op:
+        batch_op.add_column(
+            sa.Column(
+                "platforms",
+                sa.JSON().with_variant(postgresql.JSONB(), "postgresql"),
+                nullable=False,
+                server_default=platforms_default,
+            )
+        )
+        batch_op.alter_column("sid", existing_type=sa.String(64), nullable=True)
 
     # link:sid 可空 + target 加长
-    op.alter_column("cps_link", "sid", existing_type=sa.String(64), nullable=True)
-    op.alter_column("cps_link", "target_url", existing_type=sa.String(1024), type_=sa.String(2048))
+    with op.batch_alter_table("cps_link") as batch_op:
+        batch_op.alter_column("sid", existing_type=sa.String(64), nullable=True)
+        batch_op.alter_column("target_url", existing_type=sa.String(1024), type_=sa.String(2048))
 
     # click:sid 可空 + 事件类型
-    op.alter_column("cps_click", "sid", existing_type=sa.String(64), nullable=True)
-    op.add_column(
-        "cps_click",
-        sa.Column("event_type", sa.String(16), nullable=False, server_default="visit"),
-    )
+    with op.batch_alter_table("cps_click") as batch_op:
+        batch_op.alter_column("sid", existing_type=sa.String(64), nullable=True)
+        batch_op.add_column(
+            sa.Column("event_type", sa.String(16), nullable=False, server_default="visit")
+        )
 
 
 def downgrade() -> None:
-    op.drop_column("cps_click", "event_type")
-    op.alter_column("cps_click", "sid", existing_type=sa.String(64), nullable=False)
-    op.alter_column("cps_link", "target_url", existing_type=sa.String(2048), type_=sa.String(1024))
-    op.alter_column("cps_link", "sid", existing_type=sa.String(64), nullable=False)
-    op.drop_column("cps_group", "platforms")
-    op.alter_column("cps_group", "sid", existing_type=sa.String(64), nullable=False)
+    with op.batch_alter_table("cps_click") as batch_op:
+        batch_op.drop_column("event_type")
+        batch_op.alter_column("sid", existing_type=sa.String(64), nullable=False)
+    with op.batch_alter_table("cps_link") as batch_op:
+        batch_op.alter_column("target_url", existing_type=sa.String(2048), type_=sa.String(1024))
+        batch_op.alter_column("sid", existing_type=sa.String(64), nullable=False)
+    with op.batch_alter_table("cps_group") as batch_op:
+        batch_op.alter_column("sid", existing_type=sa.String(64), nullable=False)
+        batch_op.drop_column("platforms")
     op.drop_column("cps_activity", "payload")