diff --git a/src/pump/_db.py b/src/pump/_db.py
index afb856d..b1af2bf 100644
--- a/src/pump/_db.py
+++ b/src/pump/_db.py
@@ -161,7 +161,7 @@ def __init__(self, raw_db_dspace_5, raw_db_utilities_5, raw_db_7):
         self.raw_db_7 = raw_db_7
 
     def _fetch_all_vals(self, db5, table_name: str, sql: str = None):
-        sql = f"SELECT * FROM {table_name}"
+        sql = sql or f"SELECT * FROM {table_name}"
         cols5 = []
         db5 = db5 or self.raw_db_dspace_5
         vals5 = db5.fetch_all(sql, col_names=cols5)
@@ -211,11 +211,16 @@ def diff_table_cmp_cols(self, db5, table_name: str, compare_arr: list, gdpr: boo
             return
         self._cmp_values(table_name, vals5, only_in_5, vals7, only_in_7, do_not_show)
 
-    def diff_table_cmp_len(self, db5, table_name: str, nonnull: list = None, gdpr: bool = True):
+    def diff_table_cmp_len(self, db5, table_name: str, nonnull: list = None, gdpr: bool = True, sql: str = None):
         nonnull = nonnull or []
+        sql_info = False
         cols5, vals5, cols7, vals7 = self._fetch_all_vals(db5, table_name)
         do_not_show = gdpr and "email" in nonnull
 
+        if len(vals5) != len(vals7) and sql is not None:
+            cols5, vals5, cols7, vals7 = self._fetch_all_vals(db5, table_name, sql)
+            sql_info = True
+
         msg = " OK " if len(vals5) == len(vals7) else " !!! WARN !!! "
         _logger.info(
             f"Table [{table_name: >20}] {msg} compared by len only v5:[{len(vals5)}], v7:[{len(vals7)}]")
@@ -230,6 +235,10 @@ def diff_table_cmp_len(self, db5, table_name: str, nonnull: list = None, gdpr: b
             _logger.info(
                 f"Table [{table_name: >20}] {msg}  NON NULL [{col_name:>15}] v5:[{len(vals5_cmp):3}], v7:[{len(vals7_cmp):3}]")
 
+        if sql_info:
+            _logger.info(
+                f"Table [{table_name: >20}]  !!! WARN !!!  SQL request: {sql}")
+
     def diff_table_sql(self, db5, table_name: str, sql5, sql7, compare, process_ftor):
         cols5 = []
         vals5 = db5.fetch_all(sql5, col_names=cols5)
@@ -274,6 +283,10 @@ def validate(self, to_validate):
                 if len(defin) == 0:
                     self.diff_table_cmp_len(db5, table_name)
 
+                cmp = defin.get("len", None)
+                if cmp is not None:
+                    self.diff_table_cmp_len(db5, table_name, None, True, cmp["sql"])
+
                 cmp = defin.get("sql", None)
                 if cmp is not None:
                     self.diff_table_sql(
diff --git a/src/pump/_item.py b/src/pump/_item.py
index b82d248..26e3ee4 100644
--- a/src/pump/_item.py
+++ b/src/pump/_item.py
@@ -25,6 +25,9 @@ class items:
         ["workspaceitem", {
         }],
         ["collection2item", {
+            "len": {
+                "sql": "select distinct collection_id, item_id from public.collection2item group by collection_id, item_id",
+            }
         }],
     ]