fix(fetch-caliber): 取数层排除半年/预测伪期间 + subjects 响应补 entity_id

R3 期间口径（仅 YYYY-MM）延伸到取数层：新增 alert_entity_scope.month_period_clause()（跨库可移植 SQL 等价式），应用到 15 个文件 26 处「按 period 倒序取最新值/最近N期」位点；dashboard 原 MySQL-only REGEXP 正则收口到同单一事实源。

GET /api/cma/subjects 响应增补 entity_id（NULL=全局标准准则科目 / N=账套私有明细），既有 10 字段语义与名称不变。

证据：pending-tasks/_reports/yanxue-20260924-cma-fetch-caliber-fixes-fullstack.md（改前/改后 A/B：F_NET_PROFIT 2026-H2/-55.0 → 2026-08/-10.46）。新增 7 例回归测试；全量 1 failed(预存在) 1473 passed，基线同项。

backend/app/api/ai_analysis.py

@@ -8,6 +8,7 @@ from app.deps import get_entity_id
 from app.auth_middleware import require_auth, require_role
 from app.models import KPIDefinition, KPIValue, KPIAlert, StrategicMap, User, ActionPlan, BudgetPlan, AISuggestion
 from app.utils.cache import get as cache_get, set as cache_set
+from app.utils.alert_entity_scope import month_period_clause
 import json, hashlib, httpx, os, urllib.request, urllib.parse
 from datetime import datetime, date
 router = APIRouter(prefix="/api/cma/ai", tags=["AI分析"],
@@ -102,6 +103,7 @@ def generate_rule_suggestions(db: Session, entity_id: int,
                 KPIValue.entity_id == entity_id,
                 KPIValue.entity_id.is_(None),
             ),
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).first()
         if not latest or latest.actual_value is None:
             continue
@@ -286,7 +288,9 @@ async def dashboard_analysis(role: str = Query("ceo"), db: Session = Depends(get
                                           KPIDefinition.status == "active").all()
     kpi_summary = []
     for k in kpis:
-        latest = db.query(KPIValue).filter(KPIValue.kpi_id == k.id).order_by(KPIValue.period.desc()).first()
+        latest = db.query(KPIValue).filter(
+            KPIValue.kpi_id == k.id, month_period_clause(KPIValue.period)
+        ).order_by(KPIValue.period.desc()).first()
         kpi_summary.append({
             "name": k.kpi_name,
             "code": k.kpi_code,
@@ -455,7 +459,9 @@ async def dashboard_analysis_stream(role: str = Query("ceo"), db: Session = Depe
     ).all()
     kpi_summary = []
     for k in kpis:
-        latest = db.query(KPIValue).filter(KPIValue.kpi_id == k.id).order_by(KPIValue.period.desc()).first()
+        latest = db.query(KPIValue).filter(
+            KPIValue.kpi_id == k.id, month_period_clause(KPIValue.period)
+        ).order_by(KPIValue.period.desc()).first()
         kpi_summary.append({
             "name": k.kpi_name, "code": k.kpi_code, "dimension": k.dimension,
             "target": k.target_value, "actual": latest.actual_value if latest else None,
@@ -505,7 +511,9 @@ async def ask_question(
     ).all()
     kpi_context = []
     for k in kpis:
-        latest = db.query(KPIValue).filter(KPIValue.kpi_id == k.id).order_by(KPIValue.period.desc()).first()
+        latest = db.query(KPIValue).filter(
+            KPIValue.kpi_id == k.id, month_period_clause(KPIValue.period)
+        ).order_by(KPIValue.period.desc()).first()
         alert = db.query(KPIAlert).filter(KPIAlert.kpi_id == k.id, KPIAlert.status == "pending").first()
         kpi_context.append(
             f"{k.kpi_name}({k.kpi_code}): 当前值={latest.actual_value if latest else '无'}"
@@ -573,7 +581,9 @@ async def review_plans(
     for p in plans:
         kpi = db.query(KPIDefinition).filter(KPIDefinition.id == p.kpi_id).first()
         kpi_name = kpi.kpi_name if kpi else "未知"
-        latest = db.query(KPIValue).filter(KPIValue.kpi_id == p.kpi_id).order_by(KPIValue.period.desc()).first()
+        latest = db.query(KPIValue).filter(
+            KPIValue.kpi_id == p.kpi_id, month_period_clause(KPIValue.period)
+        ).order_by(KPIValue.period.desc()).first()
         plan_text.append(
             f"- {p.title}\n"
             f"  关联KPI: {kpi_name}(当前值: {latest.actual_value if latest else '无'})\n"

backend/app/api/analysis_results.py

@@ -20,6 +20,7 @@ from app.database import get_db
 from app.deps import get_entity_id
 from app.auth_middleware import require_auth
 from app.models import AnalysisResult, KPIValue, KPIDefinition, OperationLog
+from app.utils.alert_entity_scope import month_period_clause
 from typing import Optional, List
 from datetime import datetime
 
@@ -287,6 +288,7 @@ async def auto_calculate_confidence(
     # 查找历史数据（趋势）
     trend_values = db.query(KPIValue).filter(
         KPIValue.kpi_id == kpi.id,
+        month_period_clause(KPIValue.period),
     ).order_by(KPIValue.period.desc()).limit(6).all()
 
     has_actual = value is not None and value.actual_value is not None

backend/app/api/bi_reports.py

@@ -14,6 +14,7 @@ from app.deps import get_entity_id
 from app.auth_middleware import require_auth, require_role
 from app.models import KPIDefinition, KPIValue, BiReportTemplate, BiReport, OperationLog, KPICausality
 from app.utils.oplog import log_op
+from app.utils.alert_entity_scope import month_period_clause
 
 logger = logging.getLogger("bi-reports")
 
@@ -230,7 +231,7 @@ def analyze_data(data: dict, db: Session = Depends(get_db)):
         if period_end:
             val_query = val_query.filter(KPIValue.period <= period_end)
 
-        latest = val_query.order_by(KPIValue.period.desc()).first()
+        latest = val_query.filter(month_period_clause(KPIValue.period)).order_by(KPIValue.period.desc()).first()
 
         # 获取趋势数据
         trend_values = val_query.order_by(KPIValue.period.asc()).limit(12).all()

backend/app/api/bot_bridge.py

@@ -21,7 +21,7 @@ from app.models.cost_model import StandardCost, ActualCost, AbcActivity, AbcAllo
 from app.models import KPICausality
 from app.risk_levels import risk_level
 # 裁定 R1/R5（2026-09-19 财务口径）：demo 账套任何写通道不产生业务预警；期间非规整月不入库（单一事实源）
-from app.utils.alert_entity_scope import entity_alert_guard, guard_alert_period
+from app.utils.alert_entity_scope import entity_alert_guard, guard_alert_period, month_period_clause
 from app.utils.oplog import log_op, SCOPE_GLOBAL
 import json
 
@@ -135,7 +135,8 @@ def bot_kpis(
 
     results = []
     for k in kpis:
-        latest = db.query(KPIValue).filter(KPIValue.kpi_id == k.id)\
+        latest = db.query(KPIValue).filter(
+                KPIValue.kpi_id == k.id, month_period_clause(KPIValue.period))\
             .order_by(KPIValue.period.desc()).first()
         results.append({
             "id": k.id, "name": k.kpi_name, "code": k.kpi_code,
@@ -166,7 +167,8 @@ def bot_kpi_history(
     kpi = db.query(KPIDefinition).filter(KPIDefinition.id == kpi_id).first()
     if not kpi or kpi.entity_id != entity_id:
         raise HTTPException(404, "KPI不存在")
-    values = db.query(KPIValue).filter(KPIValue.kpi_id == kpi_id)\
+    values = db.query(KPIValue).filter(
+            KPIValue.kpi_id == kpi_id, month_period_clause(KPIValue.period))\
         .order_by(KPIValue.period.desc()).limit(limit).all()
     return {
         "kpi": {"id": kpi.id, "name": kpi.kpi_name, "code": kpi.kpi_code, "unit": kpi.unit},

backend/app/api/bot_kpis.py

@@ -8,6 +8,7 @@ from app.database import get_db
 from app.auth_middleware import require_auth
 from app.deps import get_entity_id
 from app.models import KPIDefinition, KPIValue
+from app.utils.alert_entity_scope import month_period_clause
 from app.risk_levels import risk_level
 
 router = APIRouter(prefix="/api/cma/bot-kpis", tags=["Bot KPI管理"],
@@ -88,6 +89,7 @@ def list_bot_kpis(
         )
         if period:
             val_query = val_query.filter(KPIValue.period == period)
+        val_query = val_query.filter(month_period_clause(KPIValue.period))
         latest_val = val_query.order_by(KPIValue.period.desc()).first()
 
         current_val = latest_val.actual_value if latest_val else None

backend/app/api/cash.py

@@ -12,6 +12,7 @@ from sqlalchemy import or_
 import pandas as pd
 from app.database import get_db
 from app.deps import get_entity_id, resolve_entity_for_request
+from app.utils.alert_entity_scope import month_period_clause
 from app.auth_middleware import require_role
 from app.models import CashPlan
 from app.utils.cash_forecast_engine import (
@@ -974,6 +975,7 @@ def _sync_cash_kpis(db: Session, entity_id: int, batch: str, periods: list) -> t
         dv = db.query(KPIValue).filter(
             KPIValue.kpi_id == debt_kpi.id,
             KPIValue.actual_value.isnot(None),
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).first()
         if dv and dv.actual_value is not None:
             short_debt_wan = round(float(dv.actual_value) / 10000, 2)  # EXT_139单位元

backend/app/api/customer_dashboard.py

@@ -8,6 +8,7 @@ from app.database import get_db
 from app.deps import get_entity_id
 from app.auth_middleware import require_auth, require_role
 from app.models import KPIDefinition, KPIValue, KPIAlert, User
+from app.utils.alert_entity_scope import month_period_clause
 import logging
 
 logger = logging.getLogger("cma.customer")
@@ -86,7 +87,7 @@ def list_customer_kpis(
             latest_val = sum(v.actual_value for v in values if v.actual_value) if values else None
             latest = type('obj', (object,), {"actual_value": latest_val, "period": f"{start_date}~{end_date}"})() if latest_val else None
         else:
-            latest = base_query.order_by(KPIValue.period.desc()).first()
+            latest = base_query.filter(month_period_clause(KPIValue.period)).order_by(KPIValue.period.desc()).first()
 
         # 最新预警
         alert = db.query(KPIAlert).filter(
@@ -127,6 +128,7 @@ def list_customer_kpis(
         # 最近6期趋势数据
         period_q = db.query(KPIValue).filter(
             KPIValue.kpi_id == k.id,
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).limit(6).all()
         period_values = [
             {"period": v.period, "value": v.actual_value}
@@ -171,6 +173,7 @@ def get_kpi_trend(
     # 获取最近N期数据
     values = db.query(KPIValue).filter(
         KPIValue.kpi_id == kpi_id,
+        month_period_clause(KPIValue.period),
     ).order_by(KPIValue.period.desc()).limit(months).all()
 
     trend_data = [

backend/app/api/dashboard.py

@@ -11,6 +11,7 @@ from app.models import KPIDefinition, KPIValue, KPIAlert, User, VoucherDetail
 from app.utils.cache import get as cache_get, set as cache_set
 from app.utils.voucher_guard import apply_voucher_guard
 from app.utils.threshold_parser import eval_threshold
+from app.utils.alert_entity_scope import month_period_clause
 # 指标方向（反向/正向）唯一权威源 = app.api.kpis.REVERSE_INDICATORS（2026-09-15 M2 准入2 收口）。
 # 本文件原自带一份字面量副本，与 kpis.py 漂移后会与「能力评分」判定相反，故改为导入。
 from app.api.kpis import REVERSE_INDICATORS
@@ -113,6 +114,7 @@ def get_bep_card(
             KPIValue.kpi_id == kpis[code].id,
             KPIValue.source_type == "derived",
             KPIValue.actual_value.isnot(None),
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc(), KPIValue.id.desc()).first()
         latest[code] = {"period": v.period, "value": v.actual_value} if v else None
 
@@ -333,7 +335,7 @@ def get_dashboard_kpis(role: str = Query("ceo"), period: str = Query("month"),
             latest_val = sum(v.actual_value for v in values if v.actual_value) if values else None
             latest = type('obj', (object,), {"actual_value": latest_val, "period": f"{start_date}~{end_date}"})() if latest_val else None
         else:
-            latest = base_query.order_by(KPIValue.period.desc()).first()
+            latest = base_query.filter(month_period_clause(KPIValue.period)).order_by(KPIValue.period.desc()).first()
         
         alert = db.query(KPIAlert).filter(
             KPIAlert.kpi_id == k.id,
@@ -396,6 +398,7 @@ def get_my_kpis(
         
         trend_values = db.query(KPIValue).filter(
             KPIValue.kpi_id == k.id,
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).limit(6).all()
         trend = [{"period": v.period, "value": v.actual_value} for v in reversed(trend_values)]
         
@@ -446,6 +449,7 @@ def get_finance_analysis(
         
         trend_values = db.query(KPIValue).filter(
             KPIValue.kpi_id == k.id,
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).limit(6).all()
         trend = [{"period": v.period, "value": v.actual_value} for v in reversed(trend_values)]
         
@@ -578,7 +582,8 @@ def predict_kpis(db: Session = Depends(get_db), entity_id: int = Depends(get_ent
 # H1/H2/FY 等汇总期行，则回退到原按 calculated_at 的取法（不改变无月期 KPI 的行为）。
 # 注意：**不能**只按 period 字典序排 —— '2026-H1'/'2026-H2' 字典序大于 '2026-08'，会把
 # 季度汇总行/半年度预估值(forecast)当成"最新"。
-_MONTH_PERIOD_REGEX = r"^[0-9]{4}-(0[1-9]|1[0-2])$"
+# 期间口径（R3 正则 / SQL 等价式）已于 2026-09-26 收口到 app/utils/alert_entity_scope.py
+# （is_month_period / month_period_clause），此处不再保留第二份副本。
 
 # 主值优先（2026-09-18 同期间重复行判据收口，项目单 project-20260918-kpi-row-priority）
 # 同一期间可能并存两行：①主值（source_type='ledger' / data_status='verified'，结账/复核口径）
@@ -600,7 +605,7 @@ def latest_kpi_value(db: Session, kpi_id: int) -> Optional[KPIValue]:
     """该 KPI 的最新可用值：月期间优先（同期内主值优先），无月期间行时回退 calculated_at 倒序。"""
     monthly = (
         db.query(KPIValue)
-        .filter(KPIValue.kpi_id == kpi_id, KPIValue.period.op("REGEXP")(_MONTH_PERIOD_REGEX))
+        .filter(KPIValue.kpi_id == kpi_id, month_period_clause(KPIValue.period))
         .order_by(
             KPIValue.period.desc(),
             _MAIN_VALUE_PRIORITY,

backend/app/api/data_quality.py

@@ -14,6 +14,7 @@ from app.deps import assert_entity_scope, get_entity_id
 from app.auth_middleware import require_auth, require_role
 from app.models import KPIDefinition, KPIValue, KpiDataQualityLog, OperationLog
 from app.api.kpis import kpi_to_dict
+from app.utils.alert_entity_scope import month_period_clause
 
 logger = logging.getLogger("data-quality")
 
@@ -74,6 +75,7 @@ def run_quality_check(db: Session = Depends(get_db), entity_id: int = Depends(ge
         values = db.query(KPIValue).filter(
             KPIValue.kpi_id == kpi.id,
             KPIValue.actual_value.isnot(None),
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).limit(12).all()
 
         # 1. 检查数据缺失
@@ -365,6 +367,7 @@ def quality_stats(db: Session = Depends(get_db), entity_id: int = Depends(get_en
         latest_val = db.query(KPIValue).filter(
             KPIValue.kpi_id == kpi.id,
             KPIValue.actual_value.isnot(None),
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).first()
         if latest_val and latest_val.calculated_at:
             if latest_val.calculated_at < stale_threshold:

backend/app/api/kpi_causality.py

@@ -13,6 +13,7 @@ from app.deps import get_entity_id
 from app.auth_middleware import require_auth, require_role
 from app.models import KPIDefinition, KPICausality, KPIValue, OperationLog
 from app.utils.oplog import log_op
+from app.utils.alert_entity_scope import month_period_clause
 from app.services.causality_verification import (
     ALL_STATUSES,
     ALL_SOURCE_TYPES,
@@ -147,7 +148,7 @@ def simulate_causality(data: dict, db: Session = Depends(get_db), entity_id: int
     )
     if period:
         query_values = query_values.filter(KPIValue.period == period)
-    latest = query_values.order_by(KPIValue.period.desc()).first()
+    latest = query_values.filter(month_period_clause(KPIValue.period)).order_by(KPIValue.period.desc()).first()
     if latest:
         current_value = latest.actual_value
 
@@ -188,6 +189,7 @@ def simulate_causality(data: dict, db: Session = Depends(get_db), entity_id: int
             tgt_val = db.query(KPIValue).filter(
                 KPIValue.kpi_id == target_id,
                 KPIValue.actual_value.isnot(None),
+                month_period_clause(KPIValue.period),
             ).order_by(KPIValue.period.desc()).first()
 
             predicted_value = None

backend/app/api/kpis.py

@@ -11,6 +11,7 @@ from app.deps import get_entity_id
 from app.auth_middleware import require_auth, require_role, filter_kpis_by_role, kpi_visible_dims
 from app.models import StrategicMap, MapObjective, KPIDefinition, KPIValue, KPIAlert, OperationLog, Entity, KPICausality, KPIHierarchy, User
 from app.utils.oplog import log_op
+from app.utils.alert_entity_scope import month_period_clause
 from app.api.kpi_governance import validate_kpi_payload, kpi_issues_message
 from app.utils.threshold_parser import (
     calc_level as _tp_calc_level,
@@ -200,6 +201,7 @@ def get_kpi_score(
         )
         if period:
             val_query = val_query.filter(KPIValue.period == period)
+        val_query = val_query.filter(month_period_clause(KPIValue.period))
         latest_val = val_query.order_by(KPIValue.period.desc()).first()
 
         current_val = latest_val.actual_value if latest_val else None
@@ -291,6 +293,7 @@ def get_kpi_glossary(
         latest_val = db.query(KPIValue).filter(
             KPIValue.kpi_id == k.id,
             KPIValue.actual_value.isnot(None),
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).first()
 
         current_value = latest_val.actual_value if latest_val else None
@@ -568,7 +571,9 @@ def list_kpi_values(
         raise HTTPException(404, "KPI不存在")
     if kpi.entity_id != entity_id:
         raise HTTPException(404, "KPI不存在")
-    vals = db.query(KPIValue).filter(KPIValue.kpi_id == kpi_id).order_by(KPIValue.period.desc()).all()
+    vals = db.query(KPIValue).filter(
+        KPIValue.kpi_id == kpi_id, month_period_clause(KPIValue.period)
+    ).order_by(KPIValue.period.desc()).all()
     return {
         "data": [{
             "id": v.id,

backend/app/api/predict.py

@@ -11,6 +11,7 @@ from app.utils.cash_forecast_engine import (
 )
 from app.database import get_db
 from app.deps import get_entity_id, resolve_entity_for_request, assert_entity_scope
+from app.utils.alert_entity_scope import month_period_clause
 from app.auth_middleware import require_auth_401
 from sqlalchemy.orm import Session
 
@@ -772,7 +773,7 @@ def _growth_quality_entity_from_db(db: Session, entity_id: int, period=None):
     )
     if period:
         q = q.filter(KPIValue.period == period)
-    rows = q.order_by(KPIValue.period.desc()).all()
+    rows = q.filter(month_period_clause(KPIValue.period)).order_by(KPIValue.period.desc()).all()
 
     entity = {"entity": ent.name}
     seen = set()

backend/app/api/reports.py

@@ -20,6 +20,7 @@ from app.database import get_db
 from app.auth_middleware import require_role, require_auth
 from app.models import KPIDefinition, KPIValue, BudgetPlan, StrategicMap, KPIAlert, User, Subject, ActionPlan, OperationLog, ReportHistory
 from app.utils.deviation_engine import calc_period_deviation, calc_period_diff, calc_deviation, get_budget_for_kpi
+from app.utils.alert_entity_scope import month_period_clause
 from app.utils.voucher_guard import apply_voucher_guard
 from app.services import report_reclass
 from app.deps import get_entity_id, assert_entity_slug_scope, resolve_session_slug
@@ -243,7 +244,8 @@ def get_kpi_trends(
     results = []
     for kpi in kpis:
         values = db.query(KPIValue).filter(
-            KPIValue.kpi_id == kpi.id
+            KPIValue.kpi_id == kpi.id,
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).limit(months).all()
         values.reverse()
 
@@ -2387,6 +2389,7 @@ def _fetch_kpi_data(db: Session, entity_id: int = 1) -> list:
         latest = db.query(KPIValue).filter(
             KPIValue.kpi_id == k.id,
             KPIValue.actual_value.isnot(None),
+            month_period_clause(KPIValue.period),
         ).order_by(KPIValue.period.desc()).first()
 
         alerts = db.query(KPIAlert).filter(

backend/app/api/subjects.py

@@ -28,7 +28,9 @@ def list_subjects(
     账套分层（2026-09-23 `subjects` 加 `entity_id` 列）：返回**全局标准准则科目**
     （`entity_id IS NULL`）∪ **本账套私有明细**（`entity_id = 会话账套`）。
     行为变更（预期）：博海会话不再看到酣客智享通明细（`100106 酒窖备用金` / `100108 友赞商户` 等）。
-    返回体字段不删不加必填（前端契约不变）。
+    2026-09-26（yanxue-20260924-cma-fetch-caliber-fixes）：响应**增补 `entity_id`**
+    （`NULL` = 全局标准准则科目；`= 会话账套` = 本账套私有明细）——原响应不含该字段，
+    共享层（51 行）与酣客私有（156 行）在界面上不可区分。既有 10 个字段语义与名称不变。
     """
     query = db.query(Subject).filter(
         Subject.is_active == 1,
@@ -59,6 +61,7 @@ def list_subjects(
                 "new_standard_category": s.new_standard_category,
                 "is_active": s.is_active,
                 "remark": s.remark,
+                "entity_id": s.entity_id,
                 "updated_at": s.updated_at.isoformat() if s.updated_at else None,
             }
             for s in subjects

backend/app/services/knowledge_service.py

@@ -20,6 +20,7 @@ from sqlalchemy.orm import Session
 from sqlalchemy import func, and_
 
 from app.models import KnowledgeEvent, KnowledgeSummary, OperationLog, KPIAlert, KPIDefinition, KPIValue, UserEntity
+from app.utils.alert_entity_scope import month_period_clause
 
 logger = logging.getLogger("cma.knowledge")
 
@@ -165,7 +166,7 @@ async def _kpi_snapshot(db: Session, entity_id: int = 1) -> list[dict]:
     for k in kpis:
         latest = (
             db.query(KPIValue)
-            .filter(KPIValue.kpi_id == k.id)
+            .filter(KPIValue.kpi_id == k.id, month_period_clause(KPIValue.period))
             .order_by(KPIValue.period.desc())
             .first()
         )

backend/app/utils/alert_entity_scope.py

@@ -87,6 +87,36 @@ def period_in_window(period, now: Optional[datetime] = None) -> bool:
     return str(period) >= window_lower_period(now)
 
 
+def month_period_clause(column):
+    """R3 的 SQL 等价式：`column` 必须落在规整月 `YYYY-MM`（供**取数层**查询使用）。
+
+    为什么取数层必须是 SQL 侧（而不是取完再在 Python 里挑）：
+      取数层的动作是「`ORDER BY period DESC` 取最新一行」（`.first()` / `.limit(N)`）。
+      伪期间 `2026-H2` 的**字符串序大于任何同年月份**（'H' > '0'），所以只要它留在排序里，
+      「最新实际期」就被它顶掉——取到的是**预测值/半年值**，而且 Python 侧再过滤也救不回来
+      （最新那一行已经不是月期间，第二行才是），`.first()` 的结果直接变成错值或空。
+      故本口径必须在 **SQL 侧**参与排序前的筛选。
+
+    跨库可移植：只用 `LENGTH` / `SUBSTR` / `BETWEEN` / `IN`（MySQL、SQLite、PostgreSQL 同名可用），
+    **不用 `REGEXP`**——SQLite 测试库未注册 REGEXP，SQL 侧正则会让单测与生产走两套语义。
+
+    与 Python 侧 `is_month_period` 同源等价：长度 7 + 第 5 位 `-` + 月份两位数字且 01–12
+    （`2026-13` 之类非法月同样排除）。禁止在调用点另写一份长度/正则判断。
+    """
+    from sqlalchemy import and_, func, or_  # 局部导入：本模块顶层不依赖 sqlalchemy 表达式 API
+
+    tens = func.substr(column, 6, 1)
+    ones = func.substr(column, 7, 1)
+    return and_(
+        func.length(column) == 7,
+        func.substr(column, 5, 1) == "-",
+        or_(
+            and_(tens == "0", ones.between("1", "9")),
+            and_(tens == "1", ones.in_(["0", "1", "2"])),
+        ),
+    )
+
+
 # ── 裁定 2b（2026-09-17）：「各 KPI 自己的最近可用期间」，单一实现 ──
 #
 # 2026-09-25（ASK-20260924-15）：原实现只在 `scripts/alert_generator.resolve_latest_period`，