diff options
Diffstat (limited to 'sql/item_cmpfunc.cc')
| -rw-r--r-- | sql/item_cmpfunc.cc | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc index 4e6301d2626..7e2d0961c14 100644 --- a/sql/item_cmpfunc.cc +++ b/sql/item_cmpfunc.cc @@ -23,6 +23,7 @@ #include "mysql_priv.h" #include <m_ctype.h> +#include "sql_select.h" static Item_result item_store_type(Item_result a,Item_result b) { @@ -476,6 +477,7 @@ longlong Item_func_eq::val_int() return value == 0 ? 1 : 0; } + /* Same as Item_func_eq, but NULL = NULL */ void Item_func_equal::fix_length_and_dec() @@ -1721,6 +1723,19 @@ void Item_cond::print(String *str) str->append(')'); } + +void Item_cond::neg_arguments() +{ + List_iterator<Item> li(list); + Item *item; + while ((item= li++)) /* Apply not transformation to the arguments */ + { + Item *new_item= item->neg_transformer(); + VOID(li.replace(new_item ? new_item : new Item_func_not(item))); + } +} + + /* Evalution of AND(expr, expr, expr ...) @@ -2334,3 +2349,91 @@ longlong Item_cond_xor::val_int() } return (longlong) result; } + +/* + Apply NOT transformation to the item and return a new one. + + SYNPOSIS + neg_transformer() + + DESCRIPTION + Transform the item using next rules: + a AND b AND ... -> NOT(a) OR NOT(b) OR ... + a OR b OR ... -> NOT(a) AND NOT(b) AND ... + NOT(a) -> a + a = b -> a != b + a != b -> a = b + a < b -> a >= b + a >= b -> a < b + a > b -> a <= b + a <= b -> a > b + IS NULL(a) -> IS NOT NULL(a) + IS NOT NULL(a) -> IS NULL(a) + + NOTE + This method is used in the eliminate_not_funcs() function. + + RETURN + New item or + NULL if we cannot apply NOT transformation (see Item::neg_transformer()). +*/ + +Item *Item_func_not::neg_transformer() /* NOT(x) -> x */ +{ + /* We should apply negation elimination to the argument of the NOT function */ + return eliminate_not_funcs(args[0]); +} + +Item *Item_func_eq::neg_transformer() /* a = b -> a != b */ +{ + return new Item_func_ne(args[0], args[1]); +} + +Item *Item_func_ne::neg_transformer() /* a != b -> a = b */ +{ + return new Item_func_eq(args[0], args[1]); +} + +Item *Item_func_lt::neg_transformer() /* a < b -> a >= b */ +{ + return new Item_func_ge(args[0], args[1]); +} + +Item *Item_func_ge::neg_transformer() /* a >= b -> a < b */ +{ + return new Item_func_lt(args[0], args[1]); +} + +Item *Item_func_gt::neg_transformer() /* a > b -> a <= b */ +{ + return new Item_func_le(args[0], args[1]); +} + +Item *Item_func_le::neg_transformer() /* a <= b -> a > b */ +{ + return new Item_func_gt(args[0], args[1]); +} + +Item *Item_func_isnull::neg_transformer() /* a IS NULL -> a IS NOT NULL */ +{ + return new Item_func_isnotnull(args[0]); +} + +Item *Item_func_isnotnull::neg_transformer() /* a IS NOT NULL -> a IS NULL */ +{ + return new Item_func_isnull(args[0]); +} + +Item *Item_cond_and::neg_transformer() /* NOT(a AND b AND ...) -> */ + /* NOT a OR NOT b OR ... */ +{ + neg_arguments(); + return new Item_cond_or(list); +} + +Item *Item_cond_or::neg_transformer() /* NOT(a OR b OR ...) -> */ + /* NOT a AND NOT b AND ... */ +{ + neg_arguments(); + return new Item_cond_and(list); +} |