diff options
Diffstat (limited to 'sql/item.cc')
| -rw-r--r-- | sql/item.cc | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/sql/item.cc b/sql/item.cc index 713e7709bcb..182632bb40f 100644 --- a/sql/item.cc +++ b/sql/item.cc @@ -4302,6 +4302,49 @@ String *Item::check_well_formed_result(String *str, bool send_error) return str; } +/* + Compare two items using a given collation + + SYNOPSIS + eq_by_collation() + item item to compare with + binary_cmp TRUE <-> compare as binaries + cs collation to use when comparing strings + + DESCRIPTION + This method works exactly as Item::eq if the collation cs coincides with + the collation of the compared objects. Otherwise, first the collations that + differ from cs are replaced for cs and then the items are compared by + Item::eq. After the comparison the original collations of items are + restored. + + RETURN + 1 compared items has been detected as equal + 0 otherwise +*/ + +bool Item::eq_by_collation(Item *item, bool binary_cmp, CHARSET_INFO *cs) +{ + CHARSET_INFO *save_cs= 0; + CHARSET_INFO *save_item_cs= 0; + if (collation.collation != cs) + { + save_cs= collation.collation; + collation.collation= cs; + } + if (item->collation.collation != cs) + { + save_item_cs= item->collation.collation; + item->collation.collation= cs; + } + bool res= eq(item, binary_cmp); + if (save_cs) + collation.collation= save_cs; + if (save_item_cs) + item->collation.collation= save_item_cs; + return res; +} + /* Create a field to hold a string value from an item |