Merge bk-internal.mysql.com:/home/bk/mysql-4.1

into  mysql.com:/home/my/mysql-4.1

2 files changed, 22 insertions, 6 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 84dbc382a52..b3d2932acf6 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -455,14 +455,18 @@ bool DTCollation::aggregate(DTCollation &dt, uint flags)
        ; // Do nothing
     }
     else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
-             derivation < dt.derivation &&
-             collation->state & MY_CS_UNICODE)
+             collation->state & MY_CS_UNICODE &&
+             (derivation < dt.derivation ||
+             (derivation == dt.derivation &&
+             !(dt.collation->state & MY_CS_UNICODE))))
     {
       // Do nothing
     }
     else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
-             dt.derivation < derivation &&
-             dt.collation->state & MY_CS_UNICODE)
+             dt.collation->state & MY_CS_UNICODE &&
+             (dt.derivation < derivation ||
+              (dt.derivation == derivation &&
+             !(collation->state & MY_CS_UNICODE))))
     {
       set(dt);
     }
diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index d316c7eaf72..52a2dedb67c 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -42,7 +42,7 @@ static void my_coll_agg_error(DTCollation &c1, DTCollation &c2,
                               const char *fname)
 {
   my_error(ER_CANT_AGGREGATE_2COLLATIONS,MYF(0),
-  	   c1.collation->name,c1.derivation_name(),
+	   c1.collation->name,c1.derivation_name(),
 	   c2.collation->name,c2.derivation_name(),
 	   fname);
 }
@@ -1188,10 +1188,22 @@ String *Item_func_substr_index::val_str(String *str)
     }
     else
     {					// Start counting at end
-      for (offset=res->length() ; ; offset-=delimeter_length-1)
+      /*
+        Negative index, start counting at the end
+      */
+      for (offset=res->length(); offset ;)
       {
+        /* 
+          this call will result in finding the position pointing to one 
+          address space less than where the found substring is located
+          in res
+        */
 	if ((int) (offset=res->strrstr(*delimeter,offset)) < 0)
 	  return res;			// Didn't find, return org string
+        /*
+          At this point, we've searched for the substring
+          the number of times as supplied by the index value
+        */
 	if (!++count)
 	{
 	  offset+=delimeter_length;