diff --git a/sql/upgrades/058.sql b/sql/upgrades/058.sql
new file mode 100644
index 000000000..055db4fb5
--- /dev/null
+++ b/sql/upgrades/058.sql
@@ -0,0 +1,44 @@
+-- SWH DB schema upgrade
+-- from_version: 57
+-- to_version: 58
+-- description: Return missing contents from batch of contents uniquely based on sha1.
+
+insert into dbversion(version, release, description)
+      values(58, now(), 'Work In Progress');
+
+-- create a temporary table called tmp_content_sha1, mimicking existing table
+-- content with only the sha1 column
+--
+create or replace function swh_mktemp_content_sha1()
+    returns void
+    language sql
+as $$
+    create temporary table tmp_content_sha1
+     (like content including defaults)
+     on commit drop;
+    alter table tmp_content_sha1 drop column if exists sha256;
+    alter table tmp_content_sha1 drop column if exists sha1_git;
+    alter table tmp_content_sha1 drop column if exists ctime;
+    alter table tmp_content_sha1 drop column if exists length;
+    alter table tmp_content_sha1 drop column if exists status;
+    alter table tmp_content_sha1 drop column if exists object_id;
+$$;
+
+
+
+-- check which entries of tmp_content_sha1 are missing from content
+--
+-- operates in bulk: 0. swh_mktemp_content_sha1(), 1. COPY to tmp_content_sha1,
+-- 2. call this function
+create or replace function swh_content_missing_per_sha1()
+    returns setof sha1
+    language plpgsql
+as $$
+begin
+    return query
+           (select sha1
+            from tmp_content_sha1 as tmp
+            where not exists
+            (select 1 from content as c where c.sha1=tmp.sha1));
+end
+$$;