FIELD() now takes in account arguments collations

mysql-test/r/func_str.result

@@ -278,6 +278,25 @@ row('A','b','c') = row('a' COLLATE latin1_bin,'b','c')
 0
 select row('A' COLLATE latin1_general_ci,'b','c') = row('a' COLLATE latin1_bin,'b','c');
 ERROR HY000: Illegal mix of collations (latin1_general_ci,EXPLICIT) and (latin1_bin,EXPLICIT) for operation '='
+select FIELD('b','A','B');
+FIELD('b','A','B')
+2
+select FIELD('B','A','B');
+FIELD('B','A','B')
+2
+select FIELD('b' COLLATE latin1_bin,'A','B');
+FIELD('b' COLLATE latin1_bin,'A','B')
+0
+select FIELD('b','A' COLLATE latin1_bin,'B');
+FIELD('b','A' COLLATE latin1_bin,'B')
+0
+select FIELD(_latin2'b','A','B');
+ERROR HY000: Illegal mix of collations for operation 'field'
+select FIELD('b',_latin2'A','B');
+ERROR HY000: Illegal mix of collations for operation 'field'
+select FIELD('b',_latin2'A','B',1);
+FIELD('b',_latin2'A','B',1)
+1
 select POSITION(_latin1'B' IN _latin1'abcd');
 POSITION(_latin1'B' IN _latin1'abcd')
 2

mysql-test/t/func_str.test

@@ -152,6 +152,19 @@ select row('A','b','c') = row('a' COLLATE latin1_bin,'b','c');
 --error 1265
 select row('A' COLLATE latin1_general_ci,'b','c') = row('a' COLLATE latin1_bin,'b','c');
 
+#
+# Test FIELD() and collations
+#
+select FIELD('b','A','B');
+select FIELD('B','A','B');
+select FIELD('b' COLLATE latin1_bin,'A','B');
+select FIELD('b','A' COLLATE latin1_bin,'B');
+--error 1269
+select FIELD(_latin2'b','A','B');
+--error 1269
+select FIELD('b',_latin2'A','B');
+select FIELD('b',_latin2'A','B',1);
+
 
 select POSITION(_latin1'B' IN _latin1'abcd');
 select POSITION(_latin1'B' IN _latin1'abcd' COLLATE latin1_bin);

sql/item_func.cc

@@ -1118,19 +1118,65 @@ longlong Item_func_locate::val_int()
 
 longlong Item_func_field::val_int()
 {
-  String *field;
-  if (!(field=item->val_str(&value)))
-    return 0;					// -1 if null ?
-  for (uint i=0 ; i < arg_count ; i++)
+  if (cmp_type == STRING_RESULT)
   {
-    String *tmp_value=args[i]->val_str(&tmp);
-    if (tmp_value && field->length() == tmp_value->length() &&
-	!memcmp(field->ptr(),tmp_value->ptr(),tmp_value->length()))
-      return (longlong) (i+1);
+    String *field;
+    if (!(field=item->val_str(&value)))
+      return 0;					// -1 if null ?
+    for (uint i=0 ; i < arg_count ; i++)
+    {
+      String *tmp_value=args[i]->val_str(&tmp);
+      if (tmp_value && field->length() == tmp_value->length() &&
+	  !sortcmp(field,tmp_value,cmp_collation.collation))
+        return (longlong) (i+1);
+    }
+  }
+  else if (cmp_type == INT_RESULT)
+  {
+    longlong val= item->val_int();
+    for (uint i=0; i < arg_count ; i++)
+    {
+      if (val == args[i]->val_int())
+ 	return (longlong) (i+1);
+    }
+  }
+  else
+  {
+    double val= item->val();
+    for (uint i=0; i < arg_count ; i++)
+    {
+      if (val == args[i]->val())
+ 	return (longlong) (i+1);
+    }
   }
   return 0;
 }
 
+void Item_func_field::fix_length_and_dec()
+{
+  maybe_null=0; max_length=3;
+  used_tables_cache|= item->used_tables();
+  const_item_cache&=  item->const_item();
+  with_sum_func= with_sum_func || item->with_sum_func;
+  
+  cmp_type= item->result_type();
+  for (uint i=0; i < arg_count ; i++)
+    cmp_type= item_cmp_type(cmp_type, args[i]->result_type());
+  
+  if (cmp_type == STRING_RESULT)
+  {
+    cmp_collation.set(item->collation);
+    for (uint i=0 ; i < arg_count ; i++)
+    {
+      if (cmp_collation.aggregate(args[i]->collation))
+      {
+	my_error(ER_CANT_AGGREGATE_NCOLLATIONS,MYF(0),func_name());
+	return;
+      }
+    }
+  }
+}
+
 
 void Item_func_field::split_sum_func(Item **ref_pointer_array,
 				     List<Item> &fields)

sql/item_func.h

@@ -624,6 +624,8 @@ class Item_func_field :public Item_int_func
 {
   Item *item;
   String value,tmp;
+  Item_result cmp_type;
+  DTCollation cmp_collation;
 public:
   Item_func_field(Item *a,List<Item> &list) :Item_int_func(list),item(a) {}
   ~Item_func_field() { delete item; }
@@ -641,13 +643,7 @@ public:
     const_item_cache&=  item->const_item();
   }
   const char *func_name() const { return "field"; }
-  void fix_length_and_dec()
-  {
-    maybe_null=0; max_length=3;
-    used_tables_cache|= item->used_tables();
-    const_item_cache&=  item->const_item();
-    with_sum_func= with_sum_func || item->with_sum_func;
-  }
+  void fix_length_and_dec();
   void set_outer_resolving()
   {
     item->set_outer_resolving();