diff --git a/alembic/versions/cps_v2_platforms.py b/alembic/versions/cps_v2_platforms.py
index e80c1a6..8311a58 100644
--- a/alembic/versions/cps_v2_platforms.py
+++ b/alembic/versions/cps_v2_platforms.py
@@ -23,39 +23,53 @@ branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
 
 
+# ⚠️ SQLite 不支持 ALTER COLUMN(改可空/类型),必须用 op.batch_alter_table(重建表)模拟;
+#    env.py 的 render_as_batch 只管 autogenerate 渲染、不会让"手写的 op.alter_column"在运行时自动 batch。
+#    batch_alter_table 在 Postgres 上等价于直接 ALTER(recreate=auto 不重建),两端通用。
 def upgrade() -> None:
-    # 活动:淘宝淘口令 / 京东链接
+    # 活动:淘宝淘口令 / 京东链接(纯 add column,SQLite 直接支持)
     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"),
-        ),
+    # 群:多平台(现有群都是美团,server_default 回填)+ sid 可空。
+    # server_default 分方言:Postgres 用 ::jsonb 显式转;SQLite 不认 ::jsonb(报 unrecognized token ":"),
+    # 用纯 JSON 字符串字面量即可(JSON 列在 SQLite 实际是 TEXT)。
+    platforms_default = (
+        "'[\"meituan\"]'::jsonb"
+        if op.get_bind().dialect.name == "postgresql"
+        else "'[\"meituan\"]'"
     )
-    op.alter_column("cps_group", "sid", existing_type=sa.String(64), nullable=True)
+    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=sa.text(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")