func_like.result, func_like.test:

  adding test case.
item_cmpfunc.cc:
  Bug#12611
  ESCAPE + LIKE do not work when the escape char is a multibyte one
  Additional fix for 8bit character sets:
  escape character must be converted into
  operation character set.

mysql-test/r/func_like.result

@@ -158,3 +158,10 @@ DROP TABLE t1;
 select _cp866'aaaaaaaaa' like _cp866'%aaaa%' collate cp866_bin;
 _cp866'aaaaaaaaa' like _cp866'%aaaa%' collate cp866_bin
 1
+set names koi8r;
+select 'andre%' like 'andre%' escape '';
+'andre%' like 'andre%' escape ''
+1
+select _cp1251'andre%' like convert('andre%' using cp1251)  escape '';
+_cp1251'andre%' like convert('andre%' using cp1251)  escape ''
+1

mysql-test/t/func_like.test

@@ -96,4 +96,21 @@ DROP TABLE t1;
 #
 select _cp866'aaaaaaaaa' like _cp866'%aaaa%' collate cp866_bin;
 
+#
+# Check 8bit escape character
+#
+set names koi8r;
+select 'andre%' like 'andre%' escape '';
+
+# Check 8bit escape character with charset conversion:
+# For "a LIKE b ESCAPE c" expressions,
+# escape character is converted into the operation character set,
+# which is result of aggregation  of character sets of "a" and "b".
+# "c" itself doesn't take part in aggregation, because its collation
+# doesn't matter, escape character is always compared binary.
+# In the example below, escape character is converted from koi8r into cp1251:
+#
+select _cp1251'andre%' like convert('andre%' using cp1251)  escape '';
+
+#
 # End of 4.1 tests

sql/item_cmpfunc.cc

@@ -2307,6 +2307,23 @@ bool Item_func_like::fix_fields(THD *thd, TABLE_LIST *tlist, Item ** ref)
       }
       else
       {
+        /*
+          In the case of 8bit character set, we pass native
+          code instead of Unicode code as "escape" argument.
+          Convert to "cs" if charset of escape differs.
+        */
+        uint32 unused;
+        if (escape_str->needs_conversion(escape_str->length(),
+                                         escape_str->charset(), cs, &unused))
+        {
+          char ch;
+          uint errors;
+          uint32 cnvlen= copy_and_convert(&ch, 1, cs, escape_str->ptr(),
+                                          escape_str->length(),
+                                          escape_str->charset(), &errors);
+          escape= cnvlen ? ch : '\\';
+        }
+        else
           escape= *(escape_str->ptr());
       }
     }