When unifying arguments for comparion, binary strings won character strings,

and comparison was done binary. Now, a binary string wins a character sting 
taking in account their derivation. That means a character field wins a
binary literal and comparison is done according to the character field
collation, not binary. 

mysql-test/r/ctype_latin1_de.result

@@ -215,21 +215,21 @@ drop table t1;
 create table t1 (word varchar(255) not null, word2 varchar(255) not null, index(word));
 insert into t1 (word) values ('ss'),(0xDF),(0xE4),('ae');
 update t1 set word2=word;
-select word, word=0xdf as t from t1 having t > 0;
+select word, word=binary 0xdf as t from t1 having t > 0;
 word	t
 	1
 select word, word=cast(0xdf AS CHAR) as t from t1 having t > 0;
 word	t
 ss	1
 	1
-select * from t1 where word=0xDF;
+select * from t1 where word=binary 0xDF;
 word	word2
 	
 select * from t1 where word=CAST(0xDF as CHAR);
 word	word2
 ss	ss
 	
-select * from t1 where word2=0xDF;
+select * from t1 where word2=binary 0xDF;
 word	word2
 	
 select * from t1 where word2=CAST(0xDF as CHAR);
@@ -244,7 +244,7 @@ select * from t1 where word= 0xe4 or word=CAST(0xe4 as CHAR);
 word	word2
 	
 ae	ae
-select * from t1 where word between 0xDF and 0xDF;
+select * from t1 where word between binary 0xDF and binary 0xDF;
 word	word2
 	
 select * from t1 where word between CAST(0xDF AS CHAR) and CAST(0xDF AS CHAR);
@@ -257,7 +257,7 @@ ae	ae
 select * from t1 where word like 'AE';
 word	word2
 ae	ae
-select * from t1 where word like 0xDF;
+select * from t1 where word like binary 0xDF;
 word	word2
 	
 select * from t1 where word like CAST(0xDF as CHAR);

mysql-test/t/ctype_latin1_de.test

@@ -52,21 +52,24 @@ drop table t1;
 # Test bug report #152 (problem with index on latin1_de)
 #
 
+#
+# The below checks both binary and character comparisons.
+#
 create table t1 (word varchar(255) not null, word2 varchar(255) not null, index(word));
 insert into t1 (word) values ('ss'),(0xDF),(0xE4),('ae');
 update t1 set word2=word;
-select word, word=0xdf as t from t1 having t > 0;
+select word, word=binary 0xdf as t from t1 having t > 0;
 select word, word=cast(0xdf AS CHAR) as t from t1 having t > 0;
-select * from t1 where word=0xDF;
+select * from t1 where word=binary 0xDF;
 select * from t1 where word=CAST(0xDF as CHAR);
-select * from t1 where word2=0xDF;
+select * from t1 where word2=binary 0xDF;
 select * from t1 where word2=CAST(0xDF as CHAR);
 select * from t1 where word='ae';
 select * from t1 where word= 0xe4 or word=CAST(0xe4 as CHAR);
-select * from t1 where word between 0xDF and 0xDF;
+select * from t1 where word between binary 0xDF and binary 0xDF;
 select * from t1 where word between CAST(0xDF AS CHAR) and CAST(0xDF AS CHAR);
 select * from t1 where word like 'ae';
 select * from t1 where word like 'AE';
-select * from t1 where word like 0xDF;
+select * from t1 where word like binary 0xDF;
 select * from t1 where word like CAST(0xDF as CHAR);
 drop table t1;

sql/item.cc

@@ -39,7 +39,7 @@ Item::Item():
 {
   marker= 0;
   maybe_null=null_value=with_sum_func=unsigned_flag=0;
-  set_charset(&my_charset_bin, DERIVATION_COERCIBLE);
+  set_charset(default_charset(), DERIVATION_COERCIBLE);
   name= 0;
   decimals= 0; max_length= 0;
   THD *thd= current_thd;
@@ -185,13 +185,6 @@ CHARSET_INFO * Item::default_charset() const
 
 bool DTCollation::aggregate(DTCollation &dt)
 {
-  if (collation == &my_charset_bin || dt.collation == &my_charset_bin)
-  {
-    collation= &my_charset_bin;
-    derivation= derivation > dt.derivation ? derivation : dt.derivation;
-    return 0;
-  }
-  
   if (!my_charset_same(collation, dt.collation))
   {
     /* 
@@ -199,13 +192,19 @@ bool DTCollation::aggregate(DTCollation &dt)
        together with character strings.
        Binaries have more precedance
     */
-    if ((derivation <= dt.derivation) && (collation == &my_charset_bin))
+    if (collation == &my_charset_bin)
     {
-      // Do nothing
+      if (derivation <= dt.derivation)
+	; // Do nothing
+      else
+	set(dt);
     }
-    else if ((dt.derivation <= derivation) && (dt.collation==&my_charset_bin))
+    else if (dt.collation == &my_charset_bin)
     {
-      set(dt);
+      if (dt.derivation <= derivation)
+        set(dt);
+      else
+       ; // Do nothing
     }
     else
     {