diff --git a/sql/diagnostic_final_production.sql b/sql/diagnostic_final_production.sql
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+-- 🔍 DIAGNOSTIC COMPLET FINAL - Production
+-- Trouvons exactement où ça bloque !
+
+-- SECTION 1: Vérification des tables et leurs structures
+SELECT 'TABLES EXISTANTES' as check_type;
+SELECT table_name, 
+       (SELECT COUNT(*) FROM information_schema.columns WHERE table_name = t.table_name) as column_count
+FROM information_schema.tables t
+WHERE table_schema = 'public' 
+AND table_name IN ('suppliers', 'groups', 'users', 'avoirs')
+ORDER BY table_name;
+
+-- SECTION 2: Structure détaillée de la table avoirs
+SELECT 'STRUCTURE TABLE AVOIRS' as check_type;
+SELECT column_name, data_type, is_nullable, column_default
+FROM information_schema.columns 
+WHERE table_name = 'avoirs' 
+ORDER BY ordinal_position;
+
+-- SECTION 3: Contraintes de la table avoirs
+SELECT 'CONTRAINTES AVOIRS' as check_type;
+SELECT conname as constraint_name, 
+       confrelid::regclass as referenced_table,
+       contype as constraint_type
+FROM pg_constraint 
+WHERE conrelid = 'avoirs'::regclass;
+
+-- SECTION 4: Données dans les tables liées
+SELECT 'DONNÉES TABLES LIÉES' as check_type;
+SELECT 'suppliers' as table_name, COUNT(*) as count FROM suppliers
+UNION ALL
+SELECT 'groups', COUNT(*) FROM groups
+UNION ALL
+SELECT 'users', COUNT(*) FROM users
+UNION ALL
+SELECT 'avoirs', COUNT(*) FROM avoirs;
+
+-- SECTION 5: Si les tables ont des données, montrez quelques exemples
+SELECT 'EXEMPLES SUPPLIERS' as check_type;
+SELECT id, name, 
+       CASE WHEN LENGTH(name) > 20 THEN LEFT(name, 20) || '...' ELSE name END as display_name
+FROM suppliers LIMIT 3;
+
+SELECT 'EXEMPLES GROUPS' as check_type;
+SELECT id, name,
+       CASE WHEN LENGTH(name) > 20 THEN LEFT(name, 20) || '...' ELSE name END as display_name
+FROM groups LIMIT 3;
+
+SELECT 'EXEMPLES USERS' as check_type;
+SELECT id, 
+       COALESCE(username, 'no_username') as username,
+       CASE WHEN LENGTH(COALESCE(username, 'no_username')) > 15 
+            THEN LEFT(COALESCE(username, 'no_username'), 15) || '...' 
+            ELSE COALESCE(username, 'no_username') END as display_username
+FROM users LIMIT 3;
+
+-- SECTION 6: Test d'insertion simple
+SELECT 'TEST INSERTION' as check_type;
+-- Seulement si toutes les tables ont des données
+SELECT CASE 
+    WHEN (SELECT COUNT(*) FROM suppliers) > 0 
+     AND (SELECT COUNT(*) FROM groups) > 0 
+     AND (SELECT COUNT(*) FROM users) > 0
+    THEN 'READY_FOR_INSERT'
+    ELSE 'MISSING_REFERENCE_DATA'
+END as insert_status;
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