perf(api): draft/list 与 stocktake/all-items 改为数据库级分页，消除 N+1

- /draft/list: 废弃 query.all() + 逐条查库存/material_base 的 N+1，
  改为原生 SQL 连表（草稿 JOIN 三张库存表 + material_base）+ LIMIT/OFFSET 分页
- /stocktake/all-items: 废弃三表 .all() + item.base 懒加载 + 内存切片，
  改为 UNION ALL + LEFT JOIN + LIMIT/OFFSET，COUNT 聚合求总数

inventory-backend/app/api/v1/inbound/stock.py

@@ -479,75 +479,88 @@ def get_drafts():
     session_id = request.args.get('session_id')
     uuid = request.args.get('uuid', '', type=str)
 
-    query = StocktakeDraft.query
+    # 防止 limit 过大（保持防御性上限，避免极端参数拖垮数据库）
+    limit = min(max(limit, 1), 500)
 
+    # ── 公共 JOIN 片段：草稿按 source_table 关联三张库存表 + material_base ──
+    join_sql = """
+        FROM stocktake_draft sd
+        LEFT JOIN stock_buy     b ON sd.source_table = 'stock_buy'     AND b.id = sd.stock_id
+        LEFT JOIN stock_semi    s ON sd.source_table = 'stock_semi'    AND s.id = sd.stock_id
+        LEFT JOIN stock_product p ON sd.source_table = 'stock_product' AND p.id = sd.stock_id
+        LEFT JOIN material_base mb ON mb.id = COALESCE(b.base_id, s.base_id, p.base_id)
+    """
+
+    # ── 动态 WHERE 条件（全部参数绑定，防止 SQL 注入）──
+    conditions = []
+    params = {}
     if session_id:
-        query = query.filter_by(session_id=session_id)
-
-    # ★ 按 uuid 精确过滤（扫码时检测该物料是否已盘）
+        conditions.append('sd.session_id = :sid')
+        params['sid'] = session_id
     if uuid:
-        query = query.filter_by(uuid=uuid)
+        conditions.append('sd.uuid = :uuid')
+        params['uuid'] = uuid
+    if keyword:
+        conditions.append("LOWER(COALESCE(b.sku, s.sku, p.sku, '')) LIKE :kw")
+        params['kw'] = f'%{keyword.lower()}%'
+    where_clause = ('WHERE ' + ' AND '.join(conditions)) if conditions else ''
 
-    # 先执行查询获取所有记录
-    drafts = query.all()
+    # ── 总数（COUNT 聚合，不再全量拉取到内存）──
+    count_sql = f'SELECT COUNT(*) {join_sql} {where_clause}'
+    total = db.session.execute(db.text(count_sql), params).scalar() or 0
 
+    # ── 真实已盘数（按库存维度去重）──
+    scanned_sql = f"""
+        SELECT COUNT(*) FROM (
+            SELECT 1 {join_sql} {where_clause}
+            GROUP BY sd.source_table, sd.stock_id
+        ) t
+    """
+    total_scanned = db.session.execute(db.text(scanned_sql), params).scalar() or 0
+
+    # ── 数据查询（真正的数据库级 LIMIT/OFFSET 分页，一次性连表取字段）──
+    offset = (page - 1) * limit
+    data_sql = f"""
+        SELECT
+            sd.id AS draft_id, sd.user_id, sd.uuid, sd.quantity, sd.scan_time,
+            sd.session_id, sd.source_table, sd.stock_id, sd.stock_qty, sd.diff_qty, sd.remark,
+            COALESCE(b.sku, s.sku, p.sku, '') AS sku,
+            mb.name AS material_name,
+            mb.spec_model AS spec_model
+        {join_sql}
+        {where_clause}
+        ORDER BY LOWER(COALESCE(b.sku, s.sku, p.sku, ''))
+        LIMIT :limit OFFSET :offset
+    """
+    query_params = dict(params)
+    query_params['limit'] = limit
+    query_params['offset'] = offset
+    rows = db.session.execute(db.text(data_sql), query_params).fetchall()
+
+    # ── 组装返回结构（仅当前页数据，无 N+1）──
     items = []
-
-    for draft in drafts:
-        # 获取 SKU 信息
-        sku = ''
-        material_name = ''
-        spec_model = ''
-
-        # 根据source_table获取对应的库存记录
-        stock_model = get_stock_model(draft.source_table)
-        if stock_model and draft.stock_id:
-            stock = stock_model.query.get(draft.stock_id)
-            if stock:
-                sku = getattr(stock, 'sku', None) or getattr(stock, 'SKU', '')
-
-                # 如果有关键词，进行 SKU 模糊匹配
-                if keyword and sku:
-                    if keyword.lower() not in sku.lower():
-                        continue
-
-                # 获取物料基础信息
-                base_id = getattr(stock, 'base_id', None)
-                if base_id:
-                    material = MaterialBase.query.get(base_id)
-                    if material:
-                        material_name = material.name
-                        spec_model = material.spec_model
-
-        item = draft.to_dict()
-        item['sku'] = sku
-        item['material_name'] = material_name
-        item['spec_model'] = spec_model
-        items.append(item)
-
-    # 按 SKU 升序排序
-    items.sort(key=lambda x: (x['sku'] or '').lower())
-
-    # 手动分页
-    total = len(items)
-    start = (page - 1) * limit
-    end = start + limit
-
-    # 计算真实的去重"已盘数量"
-    counted_items_set = set()
-    for draft_item in items:
-        # 兼容判断 quantity 或 qty_actual
-        if draft_item.get('quantity') is not None or draft_item.get('qty_actual') is not None:
-            unique_key = f"{draft_item.get('source_table', '')}_{draft_item.get('stock_id', '')}"
-            counted_items_set.add(unique_key)
-    total_scanned_unique = len(counted_items_set)
-
-    paginated_items = items[start:end]
+    for row in rows:
+        items.append({
+            'id': row.draft_id,
+            'user_id': row.user_id,
+            'uuid': row.uuid,
+            'quantity': float(row.quantity or 1),
+            'scan_time': row.scan_time.strftime('%Y-%m-%d %H:%M:%S') if row.scan_time else None,
+            'session_id': row.session_id,
+            'source_table': row.source_table,
+            'stock_id': row.stock_id,
+            'stock_qty': float(row.stock_qty or 0),
+            'diff_qty': float(row.diff_qty or 0),
+            'remark': row.remark,
+            'sku': row.sku or '',
+            'material_name': row.material_name or '',
+            'spec_model': row.spec_model or ''
+        })
 
     return jsonify({
-        'items': paginated_items,
+        'items': items,
         'total': total,
-        'total_scanned': total_scanned_unique,
+        'total_scanned': total_scanned,
         'page': page,
         'limit': limit
     }), 200
@@ -1616,98 +1629,85 @@ def get_all_stocktake_items():
         page = max(1, request.args.get('page', 1, type=int))
         pageSize = min(200, max(1, request.args.get('pageSize', 50, type=int)))
 
-        all_items = []
+        # ── 原生 SQL：UNION ALL 三张库存表 + LEFT JOIN material_base，数据库级分页 ──
+        # 注意：stock_product 表没有 batch_number 列，故第三个分支直接用 serial_number。
+        union_sql = """
+            SELECT id, 'stock_buy' AS source_table, sku, barcode,
+                   stock_quantity AS stock_qty, available_quantity, warehouse_location, base_id,
+                   COALESCE(batch_number, serial_number, '') AS batch_no
+            FROM stock_buy WHERE stock_quantity > 0
+            UNION ALL
+            SELECT id, 'stock_semi' AS source_table, sku, barcode,
+                   stock_quantity, available_quantity, warehouse_location, base_id,
+                   COALESCE(batch_number, serial_number, '') AS batch_no
+            FROM stock_semi WHERE stock_quantity > 0
+            UNION ALL
+            SELECT id, 'stock_product' AS source_table, sku, barcode,
+                   stock_quantity, available_quantity, warehouse_location, base_id,
+                   serial_number AS batch_no
+            FROM stock_product WHERE stock_quantity > 0
+        """
 
-        # 1. 采购件
-        buy_query = StockBuy.query.filter(StockBuy.stock_quantity > 0)
+        # ── 动态 WHERE（SKU / 物料名 / 规格 模糊搜索）──
+        conditions = []
+        params = {}
         if keyword:
-            buy_query = buy_query.join(MaterialBase, StockBuy.base_id == MaterialBase.id).filter(
-                db.or_(
-                    StockBuy.sku.ilike(f'%{keyword}%'),
-                    MaterialBase.name.ilike(f'%{keyword}%'),
-                    MaterialBase.spec_model.ilike(f'%{keyword}%')
-                )
-            )
-        for item in buy_query.all():
-            all_items.append({
-                'id': item.id,
-                'sku': item.sku or '',
-                'barcode': item.barcode or '',
-                'batch_no': getattr(item, 'batch_number', None) or getattr(item, 'sn', None) or getattr(item, 'serial_number', None) or '',
-                'material_name': item.base.name if item.base else '',
-                'spec_model': item.base.spec_model if item.base else '',
-                'stock_qty': float(item.stock_quantity or 0),
-                'available_qty': float(item.available_quantity or 0),
-                'source_table': 'stock_buy',
-                'warehouse_location': item.warehouse_location or ''
+            conditions.append("(LOWER(cs.sku) LIKE :kw OR LOWER(mb.name) LIKE :kw OR LOWER(mb.spec_model) LIKE :kw)")
+            params['kw'] = f'%{keyword.lower()}%'
+        where_clause = ('WHERE ' + ' AND '.join(conditions)) if conditions else ''
+
+        # 总数（COUNT 聚合，不再全量加载）
+        count_sql = f"""
+            SELECT COUNT(*) FROM ( {union_sql} ) cs
+            LEFT JOIN material_base mb ON mb.id = cs.base_id
+            {where_clause}
+        """
+        total = db.session.execute(db.text(count_sql), params).scalar() or 0
+
+        # 数据查询（真正的数据库级 LIMIT/OFFSET 分页）
+        offset = (page - 1) * pageSize
+        data_sql = f"""
+            SELECT cs.id, cs.source_table, cs.sku, cs.barcode, cs.batch_no,
+                   cs.stock_qty, cs.available_quantity, cs.warehouse_location,
+                   mb.name AS material_name, mb.spec_model AS spec_model
+            FROM ( {union_sql} ) cs
+            LEFT JOIN material_base mb ON mb.id = cs.base_id
+            {where_clause}
+            ORDER BY LOWER(cs.sku)
+            LIMIT :limit OFFSET :offset
+        """
+        query_params = dict(params)
+        query_params['limit'] = pageSize
+        query_params['offset'] = offset
+        rows = db.session.execute(db.text(data_sql), query_params).fetchall()
+
+        # ── 组装当前页数据（无 item.base 懒加载 N+1）──
+        paged = []
+        for row in rows:
+            paged.append({
+                'id': row.id,
+                'sku': row.sku or '',
+                'barcode': row.barcode or '',
+                'batch_no': row.batch_no or '',
+                'material_name': row.material_name or '',
+                'spec_model': row.spec_model or '',
+                'stock_qty': float(row.stock_qty or 0),
+                'available_qty': float(row.available_quantity or 0),
+                'source_table': row.source_table,
+                'warehouse_location': row.warehouse_location or ''
             })
 
-        # 2. 半成品
-        if StockSemi:
-            semi_query = StockSemi.query.filter(StockSemi.stock_quantity > 0)
-            if keyword:
-                semi_query = semi_query.join(MaterialBase, StockSemi.base_id == MaterialBase.id).filter(
-                    db.or_(
-                        StockSemi.sku.ilike(f'%{keyword}%'),
-                        MaterialBase.name.ilike(f'%{keyword}%'),
-                        MaterialBase.spec_model.ilike(f'%{keyword}%')
-                    )
-                )
-            for item in semi_query.all():
-                all_items.append({
-                    'id': item.id,
-                    'sku': item.sku or '',
-                    'barcode': item.barcode or '',
-                    'batch_no': getattr(item, 'batch_number', None) or getattr(item, 'sn', None) or getattr(item, 'serial_number', None) or '',
-                    'material_name': item.base.name if item.base else '',
-                    'spec_model': item.base.spec_model if item.base else '',
-                    'stock_qty': float(item.stock_quantity or 0),
-                    'available_qty': float(item.available_quantity or 0),
-                    'source_table': 'stock_semi',
-                    'warehouse_location': item.warehouse_location or ''
-                })
-
-        # 3. 成品
-        if StockProduct:
-            product_query = StockProduct.query.filter(StockProduct.stock_quantity > 0)
-            if keyword:
-                product_query = product_query.join(MaterialBase, StockProduct.base_id == MaterialBase.id).filter(
-                    db.or_(
-                        StockProduct.sku.ilike(f'%{keyword}%'),
-                        MaterialBase.name.ilike(f'%{keyword}%'),
-                        MaterialBase.spec_model.ilike(f'%{keyword}%')
-                    )
-                )
-            for item in product_query.all():
-                all_items.append({
-                    'id': item.id,
-                    'sku': item.sku or '',
-                    'barcode': item.barcode or '',
-                    'batch_no': getattr(item, 'batch_number', None) or getattr(item, 'sn', None) or getattr(item, 'serial_number', None) or '',
-                    'material_name': item.base.name if item.base else '',
-                    'spec_model': item.base.spec_model if item.base else '',
-                    'stock_qty': float(item.stock_quantity or 0),
-                    'available_qty': float(item.available_quantity or 0),
-                    'source_table': 'stock_product',
-                    'warehouse_location': item.warehouse_location or ''
-                })
-
-        # 按 SKU 排序
-        all_items.sort(key=lambda x: (x['sku'] or '').lower())
-
-        # ★ 分页切片
-        total = len(all_items)
-        start = (page - 1) * pageSize
-        paged = all_items[start:start + pageSize]
-
-        # 统计已盘数量（该 session 下已扫的）
+        # 统计已盘数量（该 session 下已扫的，SQL COUNT 聚合）
         session_id = request.args.get('session_id', '', type=str)
         total_scanned = 0
         if session_id:
-            from app.models.inbound.stocktake import StocktakeDraft
-            total_scanned = StocktakeDraft.query.filter(
-                StocktakeDraft.session_id == session_id
-            ).count()
+            scanned_sql = """
+                SELECT COUNT(DISTINCT (source_table, stock_id))
+                FROM stocktake_draft WHERE session_id = :sid
+            """
+            total_scanned = db.session.execute(
+                db.text(scanned_sql), {'sid': session_id}
+            ).scalar() or 0
 
         return jsonify({
             'code': 200,