Initial version of query showing messages without date field.

pg/dateless.sql

@@ -0,0 +1,31 @@
+/* Select all rows from left table which aren't in right table.
+
+   SELECT  l.*
+   FROM    t_left l
+   LEFT JOIN t_right r
+   ON      r.value = l.value
+   WHERE   r.value IS NULL
+ */
+
+/*
+   TODO Add another layer of JOINs to show the value where name='Received' for
+   the missing hashes.  Maybe we can parse dates from there.
+ */
+SELECT
+    l.hash, r.value
+FROM
+    original l
+LEFT JOIN (
+    SELECT
+        hash,
+        value
+    FROM
+        search_header
+    WHERE
+        name = 'Date'
+    ) r
+ON
+    r.hash = l.hash
+WHERE
+    r.hash IS NULL
+;