diff options
Diffstat (limited to 'sql/item_cmpfunc.h')
| -rw-r--r-- | sql/item_cmpfunc.h | 71 |
1 files changed, 52 insertions, 19 deletions
diff --git a/sql/item_cmpfunc.h b/sql/item_cmpfunc.h index d4a1c6b1384..5d11057228c 100644 --- a/sql/item_cmpfunc.h +++ b/sql/item_cmpfunc.h @@ -48,6 +48,14 @@ class Arg_comparator: public Sql_alloc THD *thd; Item *a_cache, *b_cache; // Cached values of a and b items // when one of arguments is NULL. + int set_compare_func(Item_result_field *owner, Item_result type); + inline int set_compare_func(Item_result_field *owner_arg) + { + return set_compare_func(owner_arg, item_cmp_type((*a)->result_type(), + (*b)->result_type())); + } + bool agg_arg_charsets_for_comparison(); + public: DTCollation cmp_collation; /* Allow owner function to use string buffers. */ @@ -58,12 +66,6 @@ public: Arg_comparator(Item **a1, Item **a2): a(a1), b(a2), set_null(TRUE), comparators(0), thd(0), a_cache(0), b_cache(0) {}; - int set_compare_func(Item_result_field *owner, Item_result type); - inline int set_compare_func(Item_result_field *owner_arg) - { - return set_compare_func(owner_arg, item_cmp_type((*a)->result_type(), - (*b)->result_type())); - } int set_cmp_func(Item_result_field *owner_arg, Item **a1, Item **a2, Item_result type); @@ -122,6 +124,8 @@ public: Item_bool_func() :Item_int_func() {} Item_bool_func(Item *a) :Item_int_func(a) {} Item_bool_func(Item *a,Item *b) :Item_int_func(a,b) {} + Item_bool_func(Item *a, Item *b, Item *c) :Item_int_func(a, b, c) {} + Item_bool_func(List<Item> &list) :Item_int_func(list) { } Item_bool_func(THD *thd, Item_bool_func *item) :Item_int_func(thd, item) {} bool is_bool_func() { return 1; } void fix_length_and_dec() { decimals=0; max_length=1; } @@ -364,7 +368,7 @@ public: virtual bool l_op() const { return 1; } }; -class Item_bool_func2 :public Item_int_func +class Item_bool_func2 :public Item_bool_func { /* Bool with 2 string args */ protected: Arg_comparator cmp; @@ -372,7 +376,7 @@ protected: public: Item_bool_func2(Item *a,Item *b) - :Item_int_func(a,b), cmp(tmp_arg, tmp_arg+1), + :Item_bool_func(a,b), cmp(tmp_arg, tmp_arg+1), abort_on_null(FALSE) { sargable= TRUE; } void fix_length_and_dec(); int set_cmp_func() @@ -389,14 +393,12 @@ public: } bool is_null() { return MY_TEST(args[0]->is_null() || args[1]->is_null()); } - bool is_bool_func() { return 1; } CHARSET_INFO *compare_collation() { return cmp.cmp_collation.collation; } - uint decimal_precision() const { return 1; } void top_level_item() { abort_on_null= TRUE; } Arg_comparator *get_comparator() { return &cmp; } void cleanup() { - Item_int_func::cleanup(); + Item_bool_func::cleanup(); cmp.cleanup(); } @@ -646,16 +648,16 @@ public: */ -class Item_func_opt_neg :public Item_int_func +class Item_func_opt_neg :public Item_bool_func { public: bool negated; /* <=> the item represents NOT <func> */ bool pred_level; /* <=> [NOT] <func> is used on a predicate level */ public: Item_func_opt_neg(Item *a, Item *b, Item *c) - :Item_int_func(a, b, c), negated(0), pred_level(0) {} + :Item_bool_func(a, b, c), negated(0), pred_level(0) {} Item_func_opt_neg(List<Item> &list) - :Item_int_func(list), negated(0), pred_level(0) {} + :Item_bool_func(list), negated(0), pred_level(0) {} public: inline void negate() { negated= !negated; } inline void top_level_item() { pred_level= 1; } @@ -686,9 +688,7 @@ public: bool fix_fields(THD *, Item **); void fix_length_and_dec(); virtual void print(String *str, enum_query_type query_type); - bool is_bool_func() { return 1; } CHARSET_INFO *compare_collation() { return cmp_collation.collation; } - uint decimal_precision() const { return 1; } bool eval_not_null_tables(uchar *opt_arg); void fix_after_pullout(st_select_lex *new_parent, Item **ref); bool count_sargable_conds(uchar *arg); @@ -1316,7 +1316,6 @@ public: longlong val_int(); bool fix_fields(THD *, Item **); void fix_length_and_dec(); - uint decimal_precision() const { return 1; } void cleanup() { uint i; @@ -1337,7 +1336,6 @@ public: enum Functype functype() const { return IN_FUNC; } const char *func_name() const { return " IN "; } bool nulls_in_row(); - bool is_bool_func() { return 1; } CHARSET_INFO *compare_collation() { return cmp_collation.collation; } bool eval_not_null_tables(uchar *opt_arg); void fix_after_pullout(st_select_lex *new_parent, Item **ref); @@ -1490,7 +1488,42 @@ public: longlong val_int(); enum Functype functype() const { return LIKE_FUNC; } optimize_type select_optimize() const; - cond_result eq_cmp_result() const { return COND_TRUE; } + cond_result eq_cmp_result() const + { + /** + We cannot always rewrite conditions as follows: + from: WHERE expr1=const AND expr1 LIKE expr2 + to: WHERE expr1=const AND const LIKE expr2 + or + from: WHERE expr1=const AND expr2 LIKE expr1 + to: WHERE expr1=const AND expr2 LIKE const + + because LIKE works differently comparing to the regular "=" operator: + + 1. LIKE performs a stricter one-character-to-one-character comparison + and does not recognize contractions and expansions. + Replacing "expr1" to "const in LIKE would make the condition + stricter in case of a complex collation. + + 2. LIKE does not ignore trailing spaces and thus works differently + from the "=" operator in case of "PAD SPACE" collations + (which are the majority in MariaDB). So, for "PAD SPACE" collations: + + - expr1=const - ignores trailing spaces + - const LIKE expr2 - does not ignore trailing spaces + - expr2 LIKE const - does not ignore trailing spaces + + Allow only "binary" for now. + It neither ignores trailing spaces nor has contractions/expansions. + + TODO: + We could still replace "expr1" to "const" in "expr1 LIKE expr2" + in case of a "PAD SPACE" collation, but only if "expr2" has '%' + at the end. + */ + return ((Item_func_like *)this)->compare_collation() == &my_charset_bin ? + COND_TRUE : COND_OK; + } const char *func_name() const { return "like"; } bool fix_fields(THD *thd, Item **ref); void cleanup(); |