diff --git a/client/mysql.cc b/client/mysql.cc
index 0c815484339..6f32cc768e4 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -1200,7 +1200,7 @@ int main(int argc,char *argv[])
 #endif
   sprintf(buff, "%s",
 #ifndef NOT_YET
-	  "Type 'help;' or '\\h' for help. Type '\\c' to clear the buffer.\n");
+	  "Type 'help;' or '\\h' for help. Type '\\c' to clear the current input statement.\n");
 #else
 	  "Type 'help [[%]function name[%]]' to get help on usage of function.\n");
 #endif
diff --git a/mysql-test/r/ctype_collate.result b/mysql-test/r/ctype_collate.result
index 69b48ee2952..b42094550bd 100644
--- a/mysql-test/r/ctype_collate.result
+++ b/mysql-test/r/ctype_collate.result
@@ -611,3 +611,22 @@ check table t1 extended;
 Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 drop table t1;
+select least(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci);
+least(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci)
+a
+create table t1
+select least(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci) as f1;
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `f1` varchar(1) CHARACTER SET latin5 NOT NULL DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t1;
+select case _latin1'a' when _latin2'b' then 1 when _latin5'c' collate
+latin5_turkish_ci then 2 else 3 end;
+case _latin1'a' when _latin2'b' then 1 when _latin5'c' collate
+latin5_turkish_ci then 2 else 3 end
+3
+select concat(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci);
+concat(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci)
+abc
diff --git a/mysql-test/t/ctype_collate.test b/mysql-test/t/ctype_collate.test
index cfef8dfe81a..6b6abbcfbcc 100644
--- a/mysql-test/t/ctype_collate.test
+++ b/mysql-test/t/ctype_collate.test
@@ -229,3 +229,17 @@ insert into t1 set a=0x6c;
 insert into t1 set a=0x4c98;
 check table t1 extended;
 drop table t1;
+
+#
+# Bug#41627 Illegal mix of collations in LEAST / GREATEST / CASE
+#
+select least(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci);
+create table t1
+select least(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci) as f1;
+show create table t1;
+drop table t1;
+
+select case _latin1'a' when _latin2'b' then 1 when _latin5'c' collate
+latin5_turkish_ci then 2 else 3 end;
+
+select concat(_latin1'a',_latin2'b',_latin5'c' collate latin5_turkish_ci);
diff --git a/sql/item.cc b/sql/item.cc
index 28ace4b114d..c446bf80355 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -1531,7 +1531,8 @@ bool DTCollation::aggregate(DTCollation &dt, uint flags)
     else
     {
       // Cannot apply conversion
-      set(0, DERIVATION_NONE, 0);
+      set(&my_charset_bin, DERIVATION_NONE,
+          (dt.repertoire|repertoire));
       return 1;
     }
   }
@@ -1614,15 +1615,31 @@ bool agg_item_collations(DTCollation &c, const char *fname,
 {
   uint i;
   Item **arg;
+  bool unknown_cs= 0;
+
   c.set(av[0]->collation);
   for (i= 1, arg= &av[item_sep]; i < count; i++, arg++)
   {
     if (c.aggregate((*arg)->collation, flags))
     {
+      if (c.derivation == DERIVATION_NONE &&
+          c.collation == &my_charset_bin)
+      {
+        unknown_cs= 1;
+        continue;
+      }
       my_coll_agg_error(av, count, fname, item_sep);
       return TRUE;
     }
   }
+
+  if (unknown_cs &&
+      c.derivation != DERIVATION_EXPLICIT)
+  {
+    my_coll_agg_error(av, count, fname, item_sep);
+    return TRUE;
+  }
+
   if ((flags & MY_COLL_DISALLOW_NONE) &&
       c.derivation == DERIVATION_NONE)
   {