From d5813a06f67d6478fed95aa9d10c44e1c1eb1076 Mon Sep 17 00:00:00 2001
From: unknown <evgen@moonbone.local>
Date: Fri, 16 Feb 2007 19:39:28 +0300
Subject: Bug#16630: The update fields of the INSERT .. SELECT .. ON DUPLICATE
 KEY UPDATE contains wrong data if the SELECT employs a temporary table.

If the UPDATE values of the INSERT .. SELECT .. ON DUPLICATE KEY UPDATE
statement contains fields from the SELECT part and the select employs a
temporary table then those fields will contain wrong values because they
aren't corrected to get data from the temporary table.

The solution is to add these fields to the selects all_fields list,
to store pointers to those fields in the selects ref_pointer_array and
to access them via Item_ref objects.

The substitution for Item_ref objects is done in the new function called
Item_field::update_value_transformer(). It is called through the
item->transform() mechanism at the end of the select_insert::prepare()
function.


sql/item.cc:
  Bug#16630: The update fields of the INSERT .. SELECT .. ON DUPLICATE KEY
  UPDATE contains wrong data if the SELECT employs a temporary table.
  The new method Item_field::update_value_transformer() is added. It
  substitutes fields in the update values list for references
  (Item_ref objects) to them.
sql/item.h:
  Bug#16630: The update fields of the INSERT .. SELECT .. ON DUPLICATE KEY
  UPDATE contains wrong data if the SELECT employs a temporary table.
  The update_value_transformer() method is added to the Item and to the
  Item_field classes.
sql/sql_insert.cc:
  Bug#16630: The update fields of the INSERT .. SELECT .. ON DUPLICATE KEY
  UPDATE contains wrong data if the SELECT employs a temporary table.
  Traverse update values and substitute fields from the select for
  references (Item_ref objects) to them.
sql/sql_select.cc:
  Bug#16630: The update fields of the INSERT .. SELECT .. ON DUPLICATE KEY
  UPDATE contains wrong data if the SELECT employs a temporary table.
  Traverse update values and substitute fields from the select for
  references (Item_ref objects) to them.
mysql-test/r/insert_select.result:
  Added a test case for bug#16630: The update fields of the INSERT .. SELECT ..
  ON DUPLICATE KEY UPDATE contains wrong data if the SELECT employs a
  temporary table.
mysql-test/t/insert_select.test:
  Added a test case for bug#16630: The update fields of the INSERT .. SELECT ..
  ON DUPLICATE KEY UPDATE contains wrong data if the SELECT employs a
  temporary table.
---
 sql/item.cc | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

(limited to 'sql/item.cc')

diff --git a/sql/item.cc b/sql/item.cc
index 95001809e9a..23193e0990c 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -4809,6 +4809,51 @@ void Item_field::update_null_value()
 }
 
 
+/*
+  Add the field to the select list and substitute it for the reference to
+  the field.
+
+  SYNOPSIS
+    Item_field::update_value_transformer()
+    select_arg      current select
+
+  DESCRIPTION
+    If the field doesn't belong to the table being inserted into then it is
+    added to the select list, pointer to it is stored in the ref_pointer_array
+    of the select and the field itself is substituted for the Item_ref object.
+    This is done in order to get correct values from update fields that
+    belongs to the SELECT part in the INSERT .. SELECT .. ON DUPLICATE KEY
+    UPDATE statement.
+
+  RETURN
+    0             if error occured
+    ref           if all conditions are met
+    this field    otherwise
+*/
+
+Item *Item_field::update_value_transformer(byte *select_arg)
+{
+  SELECT_LEX *select= (SELECT_LEX*)select_arg;
+  DBUG_ASSERT(fixed);
+
+  if (field->table != select->context.table_list->table &&
+      type() != Item::TRIGGER_FIELD_ITEM)
+  {
+    List<Item> *all_fields= &select->join->all_fields;
+    Item **ref_pointer_array= select->ref_pointer_array;
+    int el= all_fields->elements;
+    Item_ref *ref;
+
+    ref_pointer_array[el]= (Item*)this;
+    all_fields->push_front((Item*)this);
+    ref= new Item_ref(&select->context, ref_pointer_array + el,
+                      table_name, field_name);
+    return ref;
+  }
+  return this;
+}
+
+
 Item_ref::Item_ref(Name_resolution_context *context_arg,
                    Item **item, const char *table_name_arg,
                    const char *field_name_arg)
-- 
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