optimize tenant with saldo query

api/additional_methods.py

@@ -31,4 +31,16 @@ def get_account_saldo(user, token_info, accountId=None):
             "statement": "SELECT sum(amount) as saldo FROM account_entry_t WHERE account=%s",
             "params": (accountId, )
         }
-    )
+    )
+
+def get_tenant_with_saldo(user, token_info):
+    return dbGetMany(user, token_info, {
+            "statement": """
+                             SELECT t.firstname, t.lastname, t.address1, sum(a.amount) AS saldo 
+                               FROM tenant_t t, account_entry_t a 
+                               WHERE a.account = t.account 
+                               GROUP BY t.firstname, t.lastname, t.address1
+                         """, 
+            "params": ()
+        }
+    )