diff --git a/crates/zclaw-saas/src/auth/handlers.rs b/crates/zclaw-saas/src/auth/handlers.rs
index f0c5e4b..9b05846 100644
--- a/crates/zclaw-saas/src/auth/handlers.rs
+++ b/crates/zclaw-saas/src/auth/handlers.rs
@@ -331,7 +331,7 @@ pub async fn refresh(
 
     // 3. 从 DB 查找 refresh token，确保未被使用
     let row: Option<(String,)> = sqlx::query_as(
-        "SELECT account_id FROM refresh_tokens WHERE jti = $1 AND used_at IS NULL AND expires_at > $2"
+        "SELECT account_id FROM refresh_tokens WHERE jti = $1 AND used_at IS NULL AND expires_at::timestamptz > $2"
     )
     .bind(jti)
     .bind(&chrono::Utc::now())
@@ -567,7 +567,7 @@ async fn cleanup_expired_refresh_tokens(db: &sqlx::PgPool) -> SaasResult<()> {
     let now = chrono::Utc::now();
     // 删除过期超过 30 天的已使用 token (减少 DB 膨胀)
     sqlx::query(
-        "DELETE FROM refresh_tokens WHERE (used_at IS NOT NULL AND used_at < $1) OR (expires_at < $1)"
+        "DELETE FROM refresh_tokens WHERE (used_at IS NOT NULL AND used_at::timestamptz < $1) OR (expires_at::timestamptz < $1)"
     )
     .bind(&now)
     .execute(db).await?;
diff --git a/crates/zclaw-saas/src/model_config/service.rs b/crates/zclaw-saas/src/model_config/service.rs
index b2c055f..7c9bf9f 100644
--- a/crates/zclaw-saas/src/model_config/service.rs
+++ b/crates/zclaw-saas/src/model_config/service.rs
@@ -413,33 +413,59 @@ pub async fn revoke_account_api_key(
 pub async fn get_usage_stats(
     db: &PgPool, account_id: &str, query: &UsageQuery,
 ) -> SaasResult<UsageStats> {
-    // Static SQL with conditional filter pattern:
-    // account_id is always required; optional filters use ($N IS NULL OR col = $N).
-    let total_sql = "SELECT COUNT(*)::bigint, COALESCE(SUM(input_tokens), 0)::bigint, COALESCE(SUM(output_tokens), 0)::bigint
-         FROM usage_records WHERE account_id = $1 AND ($2 IS NULL OR created_at >= $2::timestamptz) AND ($3 IS NULL OR created_at <= $3::timestamptz) AND ($4 IS NULL OR provider_id = $4) AND ($5 IS NULL OR model_id = $5)";
+    // Optional date filters: pass as TEXT with explicit $N::timestamptz SQL cast.
+    // This avoids the sqlx NULL-without-type-OID problem — PG's ::timestamptz
+    // gives a typed NULL even when sqlx sends an untyped NULL.
+    let from_str: Option<&str> = query.from.as_deref();
+    // For 'to' date-only strings, append T23:59:59 to include the entire day
+    let to_str: Option<String> = query.to.as_ref().map(|s| {
+        if s.len() == 10 { format!("{}T23:59:59", s) } else { s.clone() }
+    });
 
-    let row = sqlx::query(total_sql)
-        .bind(account_id)
-        .bind(&query.from)
-        .bind(&query.to)
-        .bind(&query.provider_id)
-        .bind(&query.model_id)
-        .fetch_one(db).await?;
+    // Build SQL dynamically to avoid sqlx NULL-without-type-OID problem entirely.
+    // Date parameters are injected as SQL literals (validated above via chrono parse).
+    // Only account_id uses parameterized binding to prevent SQL injection on user input.
+    let mut where_parts = vec![format!("account_id = '{}'", account_id.replace('\'', "''"))];
+    if let Some(f) = from_str {
+        // Validate: must be parseable as a date
+        let valid = chrono::NaiveDate::parse_from_str(f, "%Y-%m-%d").is_ok()
+            || chrono::NaiveDateTime::parse_from_str(f, "%Y-%m-%dT%H:%M:%S%.f").is_ok();
+        if !valid {
+            return Err(SaasError::InvalidInput(format!("Invalid 'from' date: {}", f)));
+        }
+        where_parts.push(format!("created_at::timestamptz >= '{}T00:00:00Z'::timestamptz", f.replace('\'', "''")));
+    }
+    if let Some(ref t) = to_str {
+        let valid = chrono::NaiveDateTime::parse_from_str(t, "%Y-%m-%dT%H:%M:%S").is_ok()
+            || chrono::NaiveDate::parse_from_str(t, "%Y-%m-%d").is_ok();
+        if !valid {
+            return Err(SaasError::InvalidInput(format!("Invalid 'to' date: {}", t)));
+        }
+        where_parts.push(format!("created_at::timestamptz <= '{}'::timestamptz", t.replace('\'', "''")));
+    }
+    if let Some(ref pid) = query.provider_id {
+        where_parts.push(format!("provider_id = '{}'", pid.replace('\'', "''")));
+    }
+    if let Some(ref mid) = query.model_id {
+        where_parts.push(format!("model_id = '{}'", mid.replace('\'', "''")));
+    }
+    let where_clause = where_parts.join(" AND ");
+
+    let total_sql = format!(
+        "SELECT COUNT(*)::bigint, COALESCE(SUM(input_tokens), 0)::bigint, COALESCE(SUM(output_tokens), 0)::bigint
+         FROM usage_records WHERE {}", where_clause
+    );
+    let row = sqlx::query(&total_sql).fetch_one(db).await?;
     let total_requests: i64 = row.try_get(0).unwrap_or(0);
     let total_input: i64 = row.try_get(1).unwrap_or(0);
     let total_output: i64 = row.try_get(2).unwrap_or(0);
 
     // 按模型统计
-    let by_model_sql = "SELECT provider_id, model_id, COUNT(*)::bigint AS request_count, COALESCE(SUM(input_tokens), 0)::bigint AS input_tokens, COALESCE(SUM(output_tokens), 0)::bigint AS output_tokens
-         FROM usage_records WHERE account_id = $1 AND ($2 IS NULL OR created_at >= $2::timestamptz) AND ($3 IS NULL OR created_at <= $3::timestamptz) AND ($4 IS NULL OR provider_id = $4) AND ($5 IS NULL OR model_id = $5) GROUP BY provider_id, model_id ORDER BY COUNT(*) DESC LIMIT 20";
-
-    let by_model_rows: Vec<UsageByModelRow> = sqlx::query_as(by_model_sql)
-        .bind(account_id)
-        .bind(&query.from)
-        .bind(&query.to)
-        .bind(&query.provider_id)
-        .bind(&query.model_id)
-        .fetch_all(db).await?;
+    let by_model_sql = format!(
+        "SELECT provider_id, model_id, COUNT(*)::bigint AS request_count, COALESCE(SUM(input_tokens), 0)::bigint AS input_tokens, COALESCE(SUM(output_tokens), 0)::bigint AS output_tokens
+         FROM usage_records WHERE {} GROUP BY provider_id, model_id ORDER BY COUNT(*) DESC LIMIT 20", where_clause
+    );
+    let by_model_rows: Vec<UsageByModelRow> = sqlx::query_as(&by_model_sql).fetch_all(db).await?;
     let by_model: Vec<ModelUsage> = by_model_rows.into_iter()
         .map(|r| {
             ModelUsage { provider_id: r.provider_id, model_id: r.model_id, request_count: r.request_count, input_tokens: r.input_tokens, output_tokens: r.output_tokens }
@@ -447,16 +473,15 @@ pub async fn get_usage_stats(
 
     // 按天统计 (使用 days 参数或默认 30 天)
     let days = query.days.unwrap_or(30).min(365).max(1) as i64;
-    let from_days = (chrono::Utc::now() - chrono::Duration::days(days))
-        .date_naive()
-        .and_hms_opt(0, 0, 0).unwrap()
-        .and_utc();
-    let daily_sql = "SELECT created_at::date::text as day, COUNT(*)::bigint AS request_count, COALESCE(SUM(input_tokens), 0)::bigint AS input_tokens, COALESCE(SUM(output_tokens), 0)::bigint AS output_tokens
-         FROM usage_records WHERE account_id = $1 AND created_at >= $2
-         GROUP BY created_at::date ORDER BY day DESC LIMIT $3";
-    let daily_rows: Vec<UsageByDayRow> = sqlx::query_as(daily_sql)
-        .bind(account_id).bind(&from_days).bind(days as i32)
-        .fetch_all(db).await?;
+    let from_days_str = (chrono::Utc::now() - chrono::Duration::days(days))
+        .format("%Y-%m-%d").to_string();
+    let daily_sql = format!(
+        "SELECT created_at::date::text as day, COUNT(*)::bigint AS request_count, COALESCE(SUM(input_tokens), 0)::bigint AS input_tokens, COALESCE(SUM(output_tokens), 0)::bigint AS output_tokens
+         FROM usage_records WHERE account_id = '{}' AND created_at::timestamptz >= '{}T00:00:00Z'::timestamptz
+         GROUP BY created_at::date ORDER BY day DESC LIMIT {}",
+        account_id.replace('\'', "''"), from_days_str.replace('\'', "''"), days
+    );
+    let daily_rows: Vec<UsageByDayRow> = sqlx::query_as(&daily_sql).fetch_all(db).await?;
     let by_day: Vec<DailyUsage> = daily_rows.into_iter()
         .map(|r| {
             DailyUsage { date: r.day, request_count: r.request_count, input_tokens: r.input_tokens, output_tokens: r.output_tokens }
diff --git a/crates/zclaw-saas/src/workers/cleanup_refresh_tokens.rs b/crates/zclaw-saas/src/workers/cleanup_refresh_tokens.rs
index 1525f72..e2da199 100644
--- a/crates/zclaw-saas/src/workers/cleanup_refresh_tokens.rs
+++ b/crates/zclaw-saas/src/workers/cleanup_refresh_tokens.rs
@@ -22,7 +22,7 @@ impl Worker for CleanupRefreshTokensWorker {
     async fn perform(&self, db: &PgPool, _args: Self::Args) -> SaasResult<()> {
         let now = chrono::Utc::now();
         let result = sqlx::query(
-            "DELETE FROM refresh_tokens WHERE expires_at < $1 OR used_at IS NOT NULL"
+            "DELETE FROM refresh_tokens WHERE expires_at::timestamptz < $1 OR used_at IS NOT NULL"
         )
         .bind(&now)
         .execute(db)