Merge bk-internal:/home/bk/mysql-5.0

into  magare.gmz:/home/kgeorge/mysql/work/merge-5.0-bugteam

3 files changed, 20 insertions, 5 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 553ba1b152c..9ff1f8c0084 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -4156,9 +4156,14 @@ static void convert_zerofill_number_to_string(Item **item, Field_num *field)
   String tmp(buff,sizeof(buff), field->charset()), *res;
 
   res= (*item)->val_str(&tmp);
-  field->prepend_zeros(res);
-  pos= (char *) sql_strmake (res->ptr(), res->length());
-  *item= new Item_string(pos, res->length(), field->charset());
+  if ((*item)->is_null())
+    *item= new Item_null();
+  else
+  {
+    field->prepend_zeros(res);
+    pos= (char *) sql_strmake (res->ptr(), res->length());
+    *item= new Item_string(pos, res->length(), field->charset());
+  }
 }
 
 
diff --git a/sql/my_decimal.h b/sql/my_decimal.h
index c661579ea66..6a0d05921ec 100644
--- a/sql/my_decimal.h
+++ b/sql/my_decimal.h
@@ -164,14 +164,23 @@ inline int check_result_and_overflow(uint mask, int result, my_decimal *val)
 inline uint my_decimal_length_to_precision(uint length, uint scale,
                                            bool unsigned_flag)
 {
-  return (uint) (length - (scale>0 ? 1:0) - (unsigned_flag ? 0:1));
+  /* Precision can't be negative thus ignore unsigned_flag when length is 0. */
+  DBUG_ASSERT(length || !scale);
+  return (uint) (length - (scale>0 ? 1:0) -
+                 (unsigned_flag || !length ? 0:1));
 }
 
 inline uint32 my_decimal_precision_to_length(uint precision, uint8 scale,
                                              bool unsigned_flag)
 {
+  /*
+    When precision is 0 it means that original length was also 0. Thus
+    unsigned_flag is ignored in this case.
+  */
+  DBUG_ASSERT(precision || !scale);
   set_if_smaller(precision, DECIMAL_MAX_PRECISION);
-  return (uint32)(precision + (scale>0 ? 1:0) + (unsigned_flag ? 0:1));
+  return (uint32)(precision + (scale>0 ? 1:0) +
+                  (unsigned_flag || !precision ? 0:1));
 }
 
 inline
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 976d7322f56..11062998e6a 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -832,6 +832,7 @@ JOIN::optimize()
                             "Impossible HAVING" : "Impossible WHERE"));
       zero_result_cause=  having_value == Item::COND_FALSE ?
                            "Impossible HAVING" : "Impossible WHERE";
+      tables= 0;
       error= 0;
       DBUG_RETURN(0);
     }