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/* Copyright (C) 2000 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* subselect Item */
#ifdef __GNUC__
#pragma interface /* gcc class implementation */
#endif
class st_select_lex;
class JOIN;
class select_subselect;
/* base class for subselects */
class Item_subselect :public Item
{
protected:
uint max_columns;
my_bool assigned; /* value already assigned to subselect */
my_bool executed; /* simple subselect is executed */
my_bool optimized; /* simple subselect is optimized */
my_bool error; /* error in query */
int exec();
virtual void assign_null()
{
null_value= 1;
}
public:
st_select_lex *select_lex;
JOIN *join;
select_subselect *result;
Item_subselect(THD *thd, st_select_lex *select_lex,
select_subselect* result);
Item_subselect(Item_subselect *item)
{
null_value= item->null_value;
decimals= item->decimals;
max_columns= item->max_columns;
assigned= item->assigned;
executed= item->executed;
select_lex= item->select_lex;
join= item->join;
result= item->result;
name= item->name;
error= item->error;
}
enum Type type() const;
bool is_null() { return null_value; }
void make_field (Send_field *);
bool fix_fields(THD *thd, TABLE_LIST *tables, Item **ref);
table_map used_tables() const;
friend class select_subselect;
};
/* single value subselect */
class Item_singleval_subselect :public Item_subselect
{
protected:
longlong int_value;
double real_value;
enum Item_result res_type;
virtual void assign_null()
{
null_value= 1;
int_value= 0;
real_value= 0;
max_length= 4;
res_type= STRING_RESULT;
}
public:
Item_singleval_subselect(THD *thd, st_select_lex *select_lex);
Item_singleval_subselect(Item_singleval_subselect *item):
Item_subselect(item)
{
int_value= item->int_value;
real_value= item->real_value;
max_length= item->max_length;
decimals= item->decimals;
res_type= item->res_type;
}
double val ();
longlong val_int ();
String *val_str (String *);
Item *new_item() { return new Item_singleval_subselect(this); }
enum Item_result result_type() const { return res_type; }
friend class select_singleval_subselect;
};
/* exists subselect */
class Item_exists_subselect :public Item_subselect
{
protected:
longlong value;
virtual void assign_null()
{
value= 0;
}
public:
Item_exists_subselect(THD *thd, st_select_lex *select_lex);
Item_exists_subselect(Item_exists_subselect *item):
Item_subselect(item)
{
value= item->value;
}
Item *new_item() { return new Item_exists_subselect(this); }
enum Item_result result_type() const { return INT_RESULT;}
longlong val_int();
double val();
String *val_str(String*);
friend class select_exists_subselect;
};
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