diff --git a/app/repository/core_ro.py b/app/repository/core_ro.py
index ec8594f..e058150 100644
--- a/app/repository/core_ro.py
+++ b/app/repository/core_ro.py
@@ -2,7 +2,8 @@
 
 from __future__ import annotations
 
-from datetime import date, datetime
+from datetime import date, datetime, time, timedelta
+from decimal import Decimal
 from typing import Any
 
 from sqlalchemy import create_engine, text
@@ -76,6 +77,30 @@ class CoreReadOnlyRepository:
                 ).mappings()
             ]
 
+    def sum_trades_on_date(self, customer_id: str, day: date) -> Decimal:
+        """当日申赎合计金额（RISK-002 累计口径：仅 confirmed 的 subscribe/redeem）。
+
+        当日 = 服务器本地时区自然日，以 traded_at 落在 [day 00:00, day+1 00:00) 为准。
+        """
+        day_start = datetime.combine(day, time.min)
+        day_end = day_start + timedelta(days=1)
+        sql = text(
+            """
+            SELECT COALESCE(SUM(amount), 0)
+            FROM core_trade
+            WHERE customer_id = :cid
+              AND trade_type IN ('subscribe', 'redeem')
+              AND trade_status = 'confirmed'
+              AND traded_at >= :day_start
+              AND traded_at < :day_end
+            """
+        )
+        with self._engine.connect() as conn:
+            total = conn.execute(
+                sql, {"cid": customer_id, "day_start": day_start, "day_end": day_end}
+            ).scalar_one()
+            return Decimal(total)
+
     def get_product(self, product_id: str) -> dict[str, Any] | None:
         sql = text("SELECT * FROM core_product WHERE product_id = :pid")
         with self._engine.connect() as conn:
diff --git a/tests/test_core_ro_sum.py b/tests/test_core_ro_sum.py
new file mode 100644
index 0000000..8df8b74
--- /dev/null
+++ b/tests/test_core_ro_sum.py
@@ -0,0 +1,83 @@
+"""core_ro.sum_trades_on_date 单测（A2 · sqlite 内存库验证 SQL 逻辑，MySQL 对照留灌库后）。"""
+
+from datetime import date, datetime
+from decimal import Decimal
+
+import pytest
+from sqlalchemy import create_engine, text
+
+from app.repository.core_ro import CoreReadOnlyRepository
+
+
+@pytest.fixture()
+def repo():
+    engine = create_engine("sqlite:///:memory:")
+    with engine.begin() as conn:
+        conn.execute(
+            text(
+                """
+                CREATE TABLE core_trade (
+                    trade_id     VARCHAR(64) PRIMARY KEY,
+                    customer_id  VARCHAR(64),
+                    product_id   VARCHAR(64),
+                    trade_type   VARCHAR(16),
+                    amount       NUMERIC(18,2),
+                    trade_status VARCHAR(16) DEFAULT 'confirmed',
+                    traded_at    TIMESTAMP
+                )
+                """
+            )
+        )
+
+    def insert(trade_id, amount, traded_at, trade_type="subscribe", status="confirmed", cid="C1"):
+        conn = engine.connect()
+        conn.execute(
+            text(
+                "INSERT INTO core_trade (trade_id, customer_id, product_id, trade_type,"
+                " amount, trade_status, traded_at)"
+                " VALUES (:tid, :cid, 'P1', :tt, :amt, :st, :at)"
+            ),
+            {"tid": trade_id, "cid": cid, "tt": trade_type, "amt": amount, "st": status, "at": traded_at},
+        )
+        conn.commit()
+        conn.close()
+
+    yield CoreReadOnlyRepository(engine=engine), insert
+    engine.dispose()
+
+
+DAY = date(2026, 9, 6)
+
+
+def _at(hour, minute=0):
+    return datetime(2026, 9, 6, hour, minute)
+
+
+def test_sum_only_confirmed_subscribe_redeem(repo):
+    r, insert = repo
+    insert("T1", "600000", _at(9))          # subscribe 计入
+    insert("T2", "400000", _at(10), "redeem")  # redeem 计入
+    insert("T3", "999999", _at(11), status="pending")     # 未确认不计
+    insert("T4", "999999", _at(12), "convert")            # convert 不计
+    assert r.sum_trades_on_date("C1", DAY) == Decimal("1000000")
+
+
+def test_sum_excludes_other_days(repo):
+    r, insert = repo
+    insert("T1", "500000", _at(9))
+    insert("T2", "500000", datetime(2026, 9, 5, 23))   # 前一日不计
+    insert("T3", "500000", datetime(2026, 9, 7, 0))    # 次日不计
+    assert r.sum_trades_on_date("C1", DAY) == Decimal("500000")
+
+
+def test_sum_empty_is_zero(repo):
+    r, _ = repo
+    assert r.sum_trades_on_date("C1", DAY) == Decimal(0)
+
+
+def test_sum_per_customer(repo):
+    r, insert = repo
+    insert("T1", "500000", _at(9), cid="C1")
+    insert("T2", "500000", _at(9), cid="C2")
+    assert r.sum_trades_on_date("C1", DAY) == Decimal("500000")
+    assert r.sum_trades_on_date("C2", DAY) == Decimal("500000")