diff options
Diffstat (limited to 'sql/item_timefunc.cc')
| -rw-r--r-- | sql/item_timefunc.cc | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc index 32813454fef..5a069aee554 100644 --- a/sql/item_timefunc.cc +++ b/sql/item_timefunc.cc @@ -2134,7 +2134,6 @@ String *Item_char_typecast::val_str(String *str) String *res; uint32 length; -#if 0 if (!charset_conversion) { if (!(res= args[0]->val_str(str))) @@ -2144,7 +2143,6 @@ String *Item_char_typecast::val_str(String *str) } } else -#endif { // Convert character set if differ uint dummy_errors; @@ -2182,9 +2180,18 @@ String *Item_char_typecast::val_str(String *str) void Item_char_typecast::fix_length_and_dec() { uint32 char_length; - charset_conversion= !my_charset_same(args[0]->collation.collation, cast_cs) && - args[0]->collation.collation != &my_charset_bin && - cast_cs != &my_charset_bin; + /* + We always force character set conversion if cast_cs + is a multi-byte character set. It garantees that the + result of CAST is a well-formed string. + For single-byte character sets we allow just to copy + from the argument. A single-byte character sets string + is always well-formed. + */ + charset_conversion= (cast_cs->mbmaxlen > 1) || + !my_charset_same(args[0]->collation.collation, cast_cs) && + args[0]->collation.collation != &my_charset_bin && + cast_cs != &my_charset_bin; collation.set(cast_cs, DERIVATION_IMPLICIT); char_length= (cast_length >= 0) ? cast_length : args[0]->max_length/args[0]->collation.collation->mbmaxlen; |