diff options
Diffstat (limited to 'sql/item.cc')
| -rw-r--r-- | sql/item.cc | 67 |
1 files changed, 42 insertions, 25 deletions
diff --git a/sql/item.cc b/sql/item.cc index 4c7b30b0410..950f27c5d69 100644 --- a/sql/item.cc +++ b/sql/item.cc @@ -183,44 +183,61 @@ CHARSET_INFO * Item::default_charset() const return current_thd->variables.collation_connection; } -bool Item::set_charset(CHARSET_INFO *cs1, Derivation co1, - CHARSET_INFO *cs2, Derivation co2) +bool DTCollation::aggregate(DTCollation &dt) { - if (cs1 == &my_charset_bin || cs2 == &my_charset_bin) + if (collation == &my_charset_bin || dt.collation == &my_charset_bin) { - set_charset(&my_charset_bin, DERIVATION_NONE); + collation= &my_charset_bin; + derivation= derivation > dt.derivation ? derivation : dt.derivation; return 0; } - - if (!my_charset_same(cs1,cs2)) - return 1; - - if (co1 < co2) + + if (!my_charset_same(collation, dt.collation)) { - set_charset(cs1, co1); + /* + We do allow to use binary strings (like BLOBS) + together with character strings. + Binaries have more precedance + */ + if ((derivation <= dt.derivation) && (collation == &my_charset_bin)) + { + // Do nothing + } + else if ((dt.derivation <= derivation) && (dt.collation==&my_charset_bin)) + { + set(dt); + } + else + { + set(0, DERIVATION_NONE); + return 1; + } } - else if (co2 < co1) + else if (derivation < dt.derivation) { - set_charset(cs2, co2); + // Do nothing } - else // co2 == co1 + else if (dt.derivation < derivation) { - if (cs1 != cs2) + set(dt); + } + else + { + if (collation == dt.collation) { - if (co1 == DERIVATION_EXPLICIT) - { - return 1; - } - else + // Do nothing + } + else + { + if (derivation == DERIVATION_EXPLICIT) { - CHARSET_INFO *bin= get_charset_by_csname(cs1->csname, MY_CS_BINSORT,MYF(0)); - if (!bin) - return 1; - set_charset(bin, DERIVATION_NONE); + set(0, DERIVATION_NONE); + return 1; } + CHARSET_INFO *bin= get_charset_by_csname(collation->csname, + MY_CS_BINSORT,MYF(0)); + set(bin, DERIVATION_NONE); } - else - set_charset(cs2, co2); } return 0; } |