diff --git a/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java b/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java
index d3aaa51..d0d410e 100644
--- a/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java
+++ b/src/com/android/providers/telephony/MmsSmsDatabaseHelper.java
@@ -396,7 +396,7 @@
         // transaction to make it faster.
         // remove orphaned threads
         db.delete("threads",
-                "_id NOT IN (SELECT DISTINCT thread_id FROM sms where thread_id NOT NULL" +
+                "_id NOT IN (SELECT DISTINCT thread_id FROM sms where thread_id NOT NULL " +
                 "UNION SELECT DISTINCT thread_id FROM pdu where thread_id NOT NULL)", null);
 
         // remove orphaned canonical_addresses