fix: Correct column names in analytics SQL queries

- Fixed getAgeDistribution: use CTE with sort_order to avoid column reference errors
- Fixed getEngagementPattern: changed user_id to logged_by and created_at to started_at
- Fixed getActivityByDay: changed created_at to started_at throughout

All queries now match the actual database schema.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

maternal-app/maternal-app-backend/src/modules/admin/dashboard/dashboard.service.ts

@@ -131,14 +131,14 @@ export class DashboardService {
   async getActivityByDay(days: number = 7) {
     const result = await this.userRepository.query(
       `SELECT
-        TO_CHAR(created_at, 'Day') as day,
+        TO_CHAR(started_at, 'Day') as day,
         SUM(CASE WHEN type = 'feeding' THEN 1 ELSE 0 END) as feeding,
         SUM(CASE WHEN type = 'sleep' THEN 1 ELSE 0 END) as sleep,
         SUM(CASE WHEN type = 'diaper' THEN 1 ELSE 0 END) as diapers
       FROM activities
-      WHERE created_at >= NOW() - INTERVAL '${days} days'
-      GROUP BY TO_CHAR(created_at, 'Day'), EXTRACT(DOW FROM created_at)
-      ORDER BY EXTRACT(DOW FROM created_at)`,
+      WHERE started_at >= NOW() - INTERVAL '${days} days'
+      GROUP BY TO_CHAR(started_at, 'Day'), EXTRACT(DOW FROM started_at)
+      ORDER BY EXTRACT(DOW FROM started_at)`,
     );
 
     return result.map((row: any) => ({
@@ -151,33 +151,36 @@ export class DashboardService {
 
   async getAgeDistribution() {
     const result = await this.userRepository.query(
-      `SELECT
-        CASE
-          WHEN age_months BETWEEN 0 AND 5 THEN '0-6 months'
-          WHEN age_months BETWEEN 6 AND 11 THEN '6-12 months'
-          WHEN age_months BETWEEN 12 AND 23 THEN '1-2 years'
-          WHEN age_months BETWEEN 24 AND 35 THEN '2-3 years'
-          WHEN age_months BETWEEN 36 AND 47 THEN '3-4 years'
-          WHEN age_months BETWEEN 48 AND 59 THEN '4-5 years'
-          ELSE '5-6 years'
-        END as age,
-        COUNT(*) as count
-      FROM (
-        SELECT EXTRACT(YEAR FROM AGE(birth_date)) * 12 + EXTRACT(MONTH FROM AGE(birth_date)) as age_months
-        FROM children
-        WHERE birth_date IS NOT NULL AND deleted_at IS NULL
-      ) ages
-      GROUP BY age
-      ORDER BY
-        CASE age
-          WHEN '0-6 months' THEN 1
-          WHEN '6-12 months' THEN 2
-          WHEN '1-2 years' THEN 3
-          WHEN '2-3 years' THEN 4
-          WHEN '3-4 years' THEN 5
-          WHEN '4-5 years' THEN 6
-          ELSE 7
-        END`,
+      `WITH age_groups AS (
+        SELECT
+          CASE
+            WHEN age_months BETWEEN 0 AND 5 THEN '0-6 months'
+            WHEN age_months BETWEEN 6 AND 11 THEN '6-12 months'
+            WHEN age_months BETWEEN 12 AND 23 THEN '1-2 years'
+            WHEN age_months BETWEEN 24 AND 35 THEN '2-3 years'
+            WHEN age_months BETWEEN 36 AND 47 THEN '3-4 years'
+            WHEN age_months BETWEEN 48 AND 59 THEN '4-5 years'
+            ELSE '5-6 years'
+          END as age,
+          CASE
+            WHEN age_months BETWEEN 0 AND 5 THEN 1
+            WHEN age_months BETWEEN 6 AND 11 THEN 2
+            WHEN age_months BETWEEN 12 AND 23 THEN 3
+            WHEN age_months BETWEEN 24 AND 35 THEN 4
+            WHEN age_months BETWEEN 36 AND 47 THEN 5
+            WHEN age_months BETWEEN 48 AND 59 THEN 6
+            ELSE 7
+          END as sort_order
+        FROM (
+          SELECT EXTRACT(YEAR FROM AGE(birth_date)) * 12 + EXTRACT(MONTH FROM AGE(birth_date)) as age_months
+          FROM children
+          WHERE birth_date IS NOT NULL AND deleted_at IS NULL
+        ) ages
+      )
+      SELECT age, COUNT(*) as count
+      FROM age_groups
+      GROUP BY age, sort_order
+      ORDER BY sort_order`,
     );
 
     return result.map((row: any) => ({
@@ -189,11 +192,11 @@ export class DashboardService {
   async getEngagementPattern(days: number = 7) {
     const result = await this.userRepository.query(
       `SELECT
-        EXTRACT(HOUR FROM created_at) as hour,
-        COUNT(DISTINCT user_id) as sessions
+        EXTRACT(HOUR FROM started_at) as hour,
+        COUNT(DISTINCT logged_by) as sessions
       FROM activities
-      WHERE created_at >= NOW() - INTERVAL '${days} days'
-      GROUP BY EXTRACT(HOUR FROM created_at)
+      WHERE started_at >= NOW() - INTERVAL '${days} days'
+      GROUP BY EXTRACT(HOUR FROM started_at)
       ORDER BY hour`,
     );