Patch two (the final one) for Bug#7306 "the server side preparedStatement

 error for LIMIT placeholder".
The patch adds grammar support for LIMIT ?, ? and changes the
type of ST_SELECT_LEX::select_limit,offset_limit from ha_rows to Item*,
so that it can point to Item_param.


mysql-test/include/ps_modify.inc:
  Fix existing tests: now LIMIT can contain placeholders.
mysql-test/include/ps_query.inc:
  Fix existing tests: now LIMIT can contain placeholders.
mysql-test/r/ps.result:
  Add basic test coverage for LIMIT ?, ? and fix test results.
mysql-test/r/ps_2myisam.result:
  Fix test results: now LIMIT can contain placeholders.
mysql-test/r/ps_3innodb.result:
  Fix test results: now LIMIT can contain placeholders.
mysql-test/r/ps_4heap.result:
  Fix test results: now LIMIT can contain placeholders.
mysql-test/r/ps_5merge.result:
  Fix test results: now LIMIT can contain placeholders.
mysql-test/r/ps_6bdb.result:
  Fix test results: now LIMIT can contain placeholders.
mysql-test/r/ps_7ndb.result:
  Fix test results: now LIMIT can contain placeholders.
mysql-test/t/ps.test:
  Add basic test coverage for LIMIT ?, ?.
sql/item.h:
  Add a short-cut for (ulonglong) val_int() to Item.
  Add a constructor to Item_int() that accepts ulonglong.
  Simplify Item_uint constructor by using the c-tor above.
sql/item_subselect.cc:
  Now select_limit has type Item *.
  We can safely create an Item in Item_exists_subselect::fix_length_and_dec():
  it will be allocated in runtime memory root and freed in the end of
  execution.
sql/sp_head.cc:
  Add a special initalization state for stored procedures to 
  be able to easily distinguish the first execution of a stored procedure
  from prepared statement prepare.
sql/sql_class.h:
  Introduce new state 'INITIALIZED_FOR_SP' to be able to easily distinguish
  the first execution of a stored procedure from prepared statement prepare.
sql/sql_derived.cc:
  - use unit->set_limit() to set unit->select_limit_cnt, offset_limit_cnt
    evreryplace. Add a warning about use of set_limit in 
  mysql_derived_filling.
sql/sql_error.cc:
  - use unit->set_limit() to set unit->select_limit_cnt, offset_limit_cnt
    evreryplace.
  - this change is also aware of bug#11095 "show warnings limit 0 returns 
  all rows instead of zero rows", so the one who merges the bugfix from
  4.1 can use local version of sql_error.cc.
sql/sql_handler.cc:
  - use unit->set_limit() to initalize 
  unit->select_limit_cnt,offset_limit_cnt everyplace.
sql/sql_lex.cc:
  Now ST_SELECT_LEX::select_limit, offset_limit have type Item *
sql/sql_lex.h:
  Now ST_SELECT_LEX::select_limit, offset_limit have type Item *
sql/sql_parse.cc:
  - use unit->set_limit() to initalize 
  unit->select_limit_cnt,offset_limit_cnt everyplace. 
  - we can create an Item_int to set global limit of a statement:
  it will be created in the runtime mem root and freed in the end of
  execution.
sql/sql_repl.cc:
  Use unit->set_limit to initialize limits.
sql/sql_select.cc:
  - select_limit is now Item* so the proper way to check for default value
  is to compare it with NULL.
sql/sql_union.cc:
  Evaluate offset_limit_cnt using the new type of ST_SELECT_LEX::offset_limit
sql/sql_view.cc:
  Now ST_SELECT_LEX::select_limit, offset_limit have type Item *
sql/sql_yacc.yy:
  Add grammar support for LIMIT ?, ? clause.

mysql-test/include/ps_modify.inc

@@ -174,11 +174,8 @@ where a=2
 limit 1';
 execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
-# currently (May 2004, Version 4.1) it is impossible
--- error 1064
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 
 --disable_query_log
 select '------ insert tests ------' as test_sequence ;

mysql-test/include/ps_query.inc

@@ -300,10 +300,8 @@ set @arg00=1;
 prepare stmt1 from ' select a,b from t1 order by a
 limit 1 ';
 execute stmt1 ;
-# currently (May 2004, Version 4.1) it is impossible
--- error 1064
-prepare stmt1 from ' select a,b from t1
-limit ? ';
+prepare stmt1 from ' select a,b from t1 limit ? ';
+execute stmt1 using @arg00;
 
 ##### parameter used in many places
 set @arg00='b' ;

mysql-test/r/ps.result

@@ -634,3 +634,44 @@ id
 3
 deallocate prepare stmt;
 drop table t1, t2;
+create table t1 (a int);
+insert into t1 (a) values (1), (2), (3), (4), (5), (6), (7), (8), (9), (10);
+prepare stmt from "select * from t1 limit ?, ?";
+set @offset=0, @limit=1;
+execute stmt using @offset, @limit;
+a
+1
+select * from t1 limit 0, 1;
+a
+1
+set @offset=3, @limit=2;
+execute stmt using @offset, @limit;
+a
+4
+5
+select * from t1 limit 3, 2;
+a
+4
+5
+prepare stmt from "select * from t1 limit ?";
+execute stmt using @limit;
+a
+1
+2
+prepare stmt from "select * from t1 where a in (select a from t1 limit ?)";
+ERROR 42000: This version of MySQL doesn't yet support 'LIMIT & IN/ALL/ANY/SOME subquery'
+prepare stmt from "select * from t1 union all select * from t1 limit ?, ?";
+set @offset=9;
+set @limit=2;
+execute stmt using @offset, @limit;
+a
+10
+1
+prepare stmt from "(select * from t1 limit ?, ?) union all
+                   (select * from t1 limit ?, ?) order by a limit ?";
+execute stmt using @offset, @limit, @offset, @limit, @limit;
+a
+10
+10
+drop table t1;
+deallocate prepare stmt;

mysql-test/r/ps_2myisam.result

@@ -444,9 +444,10 @@ limit 1 ';
 execute stmt1 ;
 a	b
 1	one
-prepare stmt1 from ' select a,b from t1
-limit ? ';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 2
+prepare stmt1 from ' select a,b from t1 limit ? ';
+execute stmt1 using @arg00;
+a	b
+1	one
 set @arg00='b' ;
 set @arg01=0 ;
 set @arg02=2 ;
@@ -1381,10 +1382,8 @@ execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
 a	b
 2	bla
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 3
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 test_sequence
 ------ insert tests ------
 delete from t1 ;

mysql-test/r/ps_3innodb.result

@@ -444,9 +444,10 @@ limit 1 ';
 execute stmt1 ;
 a	b
 1	one
-prepare stmt1 from ' select a,b from t1
-limit ? ';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 2
+prepare stmt1 from ' select a,b from t1 limit ? ';
+execute stmt1 using @arg00;
+a	b
+1	one
 set @arg00='b' ;
 set @arg01=0 ;
 set @arg02=2 ;
@@ -1364,10 +1365,8 @@ execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
 a	b
 2	bla
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 3
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 test_sequence
 ------ insert tests ------
 delete from t1 ;

mysql-test/r/ps_4heap.result

@@ -445,9 +445,10 @@ limit 1 ';
 execute stmt1 ;
 a	b
 1	one
-prepare stmt1 from ' select a,b from t1
-limit ? ';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 2
+prepare stmt1 from ' select a,b from t1 limit ? ';
+execute stmt1 using @arg00;
+a	b
+1	one
 set @arg00='b' ;
 set @arg01=0 ;
 set @arg02=2 ;
@@ -1365,10 +1366,8 @@ execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
 a	b
 2	bla
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 3
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 test_sequence
 ------ insert tests ------
 delete from t1 ;

mysql-test/r/ps_5merge.result

@@ -487,9 +487,10 @@ limit 1 ';
 execute stmt1 ;
 a	b
 1	one
-prepare stmt1 from ' select a,b from t1
-limit ? ';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 2
+prepare stmt1 from ' select a,b from t1 limit ? ';
+execute stmt1 using @arg00;
+a	b
+1	one
 set @arg00='b' ;
 set @arg01=0 ;
 set @arg02=2 ;
@@ -1407,10 +1408,8 @@ execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
 a	b
 2	bla
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 3
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 test_sequence
 ------ insert tests ------
 delete from t1 ;
@@ -3500,9 +3499,10 @@ limit 1 ';
 execute stmt1 ;
 a	b
 1	one
-prepare stmt1 from ' select a,b from t1
-limit ? ';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 2
+prepare stmt1 from ' select a,b from t1 limit ? ';
+execute stmt1 using @arg00;
+a	b
+1	one
 set @arg00='b' ;
 set @arg01=0 ;
 set @arg02=2 ;
@@ -4420,10 +4420,8 @@ execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
 a	b
 2	bla
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 3
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 test_sequence
 ------ insert tests ------
 delete from t1 ;

mysql-test/r/ps_6bdb.result

@@ -444,9 +444,10 @@ limit 1 ';
 execute stmt1 ;
 a	b
 1	one
-prepare stmt1 from ' select a,b from t1
-limit ? ';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 2
+prepare stmt1 from ' select a,b from t1 limit ? ';
+execute stmt1 using @arg00;
+a	b
+1	one
 set @arg00='b' ;
 set @arg01=0 ;
 set @arg02=2 ;
@@ -1364,10 +1365,8 @@ execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
 a	b
 2	bla
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 3
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 test_sequence
 ------ insert tests ------
 delete from t1 ;

mysql-test/r/ps_7ndb.result

-use test;
-drop table if exists t1, t9 ;
-create table t1
+use test; drop table if exists t1, t9 ; create table t1
 (
 a int, b varchar(30),
 primary key(a)
@@ -1364,10 +1362,8 @@ execute stmt1 ;
 select a,b from t1 where b = 'bla' ;
 a	b
 2	bla
-prepare stmt1 from 'update t1 set b=''bla''
-where a=2
-limit ?';
-ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 3
+prepare stmt1 from 'update t1 set b=''bla'' where a=2 limit ?';
+execute stmt1 using @arg00;
 test_sequence
 ------ insert tests ------
 delete from t1 ;

mysql-test/t/ps.test

@@ -664,3 +664,32 @@ select t2.id from t2, t1 where (t1.id=1 and t2.t1_id=t1.id);
 
 deallocate prepare stmt;
 drop table t1, t2;
+
+#
+# Bug#7306 LIMIT ?, ? and also WL#1785 " Prepared statements: implement
+# support for placeholders in LIMIT clause."
+# Add basic test coverage for the feature.
+# 
+create table t1 (a int);
+insert into t1 (a) values (1), (2), (3), (4), (5), (6), (7), (8), (9), (10);
+prepare stmt from "select * from t1 limit ?, ?";
+set @offset=0, @limit=1;
+execute stmt using @offset, @limit;
+select * from t1 limit 0, 1;
+set @offset=3, @limit=2;
+execute stmt using @offset, @limit;
+select * from t1 limit 3, 2;
+prepare stmt from "select * from t1 limit ?";
+execute stmt using @limit;
+--error 1235
+prepare stmt from "select * from t1 where a in (select a from t1 limit ?)";
+prepare stmt from "select * from t1 union all select * from t1 limit ?, ?";
+set @offset=9;
+set @limit=2;
+execute stmt using @offset, @limit;
+prepare stmt from "(select * from t1 limit ?, ?) union all
+                   (select * from t1 limit ?, ?) order by a limit ?";
+execute stmt using @offset, @limit, @offset, @limit, @limit;
+
+drop table t1;
+deallocate prepare stmt;

sql/item.h

@@ -334,6 +334,11 @@ class Item {
       If value is not null null_value flag will be reset to FALSE.
   */
   virtual longlong val_int()=0;
+  /*
+    This is just a shortcut to avoid the cast. You should still use
+    unsigned_flag to check the sign of the item.
+  */
+  inline ulonglong val_uint() { return (ulonglong) val_int(); }
   /*
     Return string representation of this item object.
 
@@ -978,10 +983,10 @@ class Item_int :public Item_num
   longlong value;
   Item_int(int32 i,uint length=11) :value((longlong) i)
     { max_length=length; fixed= 1; }
-#ifdef HAVE_LONG_LONG
   Item_int(longlong i,uint length=21) :value(i)
     { max_length=length; fixed= 1; }
-#endif
+  Item_int(ulonglong i, uint length= 21) :value((longlong)i)
+    { max_length=length; fixed= 1; unsigned_flag= 1; }
   Item_int(const char *str_arg,longlong i,uint length) :value(i)
     { max_length=length; name=(char*) str_arg; fixed= 1; }
   Item_int(const char *str_arg, uint length=64);
@@ -1019,9 +1024,8 @@ class Item_uint :public Item_int
 {
 public:
   Item_uint(const char *str_arg, uint length);
+  Item_uint(uint32 i) :Item_int((ulonglong) i, 10) {}
   Item_uint(const char *str_arg, longlong i, uint length);
-  Item_uint(uint32 i) :Item_int((longlong) i, 10) 
-    { unsigned_flag= 1; }
   double val_real()
     { DBUG_ASSERT(fixed == 1); return ulonglong2double((ulonglong)value); }
   String *val_str(String*);

sql/item_subselect.cc

@@ -602,8 +602,8 @@ void Item_exists_subselect::fix_length_and_dec()
    decimals= 0;
    max_length= 1;
    max_columns= engine->cols();
-   /* We need only 1 row to determinate existence */
-  unit->global_parameters->select_limit= 1;
+  /* We need only 1 row to determine existence */
+  unit->global_parameters->select_limit= new Item_int(1);
 }
 
 double Item_exists_subselect::val_real()

sql/sp_head.cc

@@ -320,7 +320,7 @@ sp_head::sp_head()
     *sp_lex_sp_key(const byte *ptr, uint *plen, my_bool first);
   DBUG_ENTER("sp_head::sp_head");
 
-  state= INITIALIZED;
+  state= INITIALIZED_FOR_SP;
   m_backpatch.empty();
   m_lex.empty();
   hash_init(&m_sptabs, system_charset_info, 0, 0, 0, sp_table_key, 0, 0);
@@ -1078,7 +1078,7 @@ sp_head::restore_thd_mem_root(THD *thd)
   DBUG_ENTER("sp_head::restore_thd_mem_root");
   Item *flist= free_list;	// The old list
   set_item_arena(thd);          // Get new free_list and mem_root
-  state= INITIALIZED;
+  state= INITIALIZED_FOR_SP;
 
   DBUG_PRINT("info", ("mem_root 0x%lx returned from thd mem root 0x%lx",
                       (ulong) &mem_root, (ulong) &thd->mem_root));

sql/sql_class.h

@@ -665,8 +665,8 @@ class Item_arena
 #endif
   enum enum_state 
   {
-    INITIALIZED= 0, PREPARED= 1, EXECUTED= 3, CONVENTIONAL_EXECUTION= 2, 
-    ERROR= -1
+    INITIALIZED= 0, INITIALIZED_FOR_SP= 1, PREPARED= 2,
+    CONVENTIONAL_EXECUTION= 3, EXECUTED= 4, ERROR= -1
   };
   
   enum_state state;
@@ -695,6 +695,7 @@ class Item_arena
   virtual Type type() const;
   virtual ~Item_arena() {};
 
+  inline bool is_stmt_prepare() const { return state == INITIALIZED; }
   inline bool is_stmt_prepare_or_first_sp_execute() const
   { return (int)state < (int)PREPARED; }
   inline bool is_first_stmt_execute() const { return state == PREPARED; }

sql/sql_derived.cc

@@ -217,6 +217,8 @@ int mysql_derived_prepare(THD *thd, LEX *lex, TABLE_LIST *orig_table_list)
     queries defined. After temporary table is filled, if this is not EXPLAIN,
     then the entire unit / node is deleted. unit is deleted if UNION is used
     for derived table and node is deleted is it is a  simple SELECT.
+    If you use this function, make sure it's not called at prepare.
+    Due to evaluation of LIMIT clause it can not be used at prepared stage.
 
   RETURN
     0	ok
@@ -245,11 +247,7 @@ int mysql_derived_filling(THD *thd, LEX *lex, TABLE_LIST *orig_table_list)
     }
     else
     {
-      unit->offset_limit_cnt= first_select->offset_limit;
-      unit->select_limit_cnt= first_select->select_limit+
-	first_select->offset_limit;
-      if (unit->select_limit_cnt < first_select->select_limit)
-	unit->select_limit_cnt= HA_POS_ERROR;
+      unit->set_limit(first_select);
       if (unit->select_limit_cnt == HA_POS_ERROR)
 	first_select->options&= ~OPTION_FOUND_ROWS;
 

sql/sql_error.cc

@@ -225,20 +225,22 @@ bool mysqld_show_warnings(THD *thd, ulong levels_to_show)
 
   MYSQL_ERROR *err;
   SELECT_LEX *sel= &thd->lex->select_lex;
-  ha_rows offset= sel->offset_limit, limit= sel->select_limit;
+  SELECT_LEX_UNIT *unit= &thd->lex->unit;
+  ha_rows idx= 0;
   Protocol *protocol=thd->protocol;
-  
+
+  unit->set_limit(sel);
+
   List_iterator_fast<MYSQL_ERROR> it(thd->warn_list);
   while ((err= it++))
   {
     /* Skip levels that the user is not interested in */
     if (!(levels_to_show & ((ulong) 1 << err->level)))
       continue;
-    if (offset)
-    {
-      offset--;
+    if (++idx <= unit->offset_limit_cnt)
       continue;
-    }
+    if (idx > unit->select_limit_cnt)
+      break;
     protocol->prepare_for_resend();
     protocol->store(warning_level_names[err->level],
 		    warning_level_length[err->level], system_charset_info);
@@ -246,8 +248,6 @@ bool mysqld_show_warnings(THD *thd, ulong levels_to_show)
     protocol->store(err->msg, strlen(err->msg), system_charset_info);
     if (protocol->write())
       DBUG_RETURN(TRUE);
-    if (!--limit)
-      break;
   }
   send_eof(thd);
   DBUG_RETURN(FALSE);

sql/sql_handler.cc

@@ -321,8 +321,8 @@ bool mysql_ha_close(THD *thd, TABLE_LIST *tables)
     key_expr
     ha_rkey_mode
     cond
-    select_limit
-    offset_limit
+    select_limit_cnt
+    offset_limit_cnt
 
   RETURN
     FALSE ok
@@ -333,7 +333,7 @@ bool mysql_ha_read(THD *thd, TABLE_LIST *tables,
                    enum enum_ha_read_modes mode, char *keyname,
                    List<Item> *key_expr,
                    enum ha_rkey_function ha_rkey_mode, Item *cond,
-                   ha_rows select_limit,ha_rows offset_limit)
+                   ha_rows select_limit_cnt, ha_rows offset_limit_cnt)
 {
   TABLE_LIST    *hash_tables;
   TABLE         *table;
@@ -429,7 +429,6 @@ bool mysql_ha_read(THD *thd, TABLE_LIST *tables,
   if (insert_fields(thd, tables, tables->db, tables->alias, &it, 0, 0))
     goto err0;
 
-  select_limit+=offset_limit;
   protocol->send_fields(&list, Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF);
 
   HANDLER_TABLES_HACK(thd);
@@ -447,7 +446,7 @@ bool mysql_ha_read(THD *thd, TABLE_LIST *tables,
 
   table->file->init_table_handle_for_HANDLER();
 
-  for (num_rows=0; num_rows < select_limit; )
+  for (num_rows=0; num_rows < select_limit_cnt; )
   {
     switch (mode) {
     case RFIRST:
@@ -535,7 +534,7 @@ bool mysql_ha_read(THD *thd, TABLE_LIST *tables,
     }
     if (cond && !cond->val_int())
       continue;
-    if (num_rows >= offset_limit)
+    if (num_rows >= offset_limit_cnt)
     {
       Item *item;
       protocol->prepare_for_resend();

sql/sql_lex.cc

@@ -1138,8 +1138,9 @@ void st_select_lex::init_select()
   order_list.elements= 0;
   order_list.first= 0;
   order_list.next= (byte**) &order_list.first;
-  select_limit= HA_POS_ERROR;
-  offset_limit= 0;
+  /* Set limit and offset to default values */
+  select_limit= 0;      /* denotes the default limit = HA_POS_ERROR */
+  offset_limit= 0;      /* denotes the default offset = 0 */
   with_sum_func= 0;
 }
 
@@ -1363,7 +1364,7 @@ ulong st_select_lex_node::get_table_join_options()
 */
 bool st_select_lex::test_limit()
 {
-  if (select_limit != HA_POS_ERROR)
+  if (select_limit != 0)
   {
     my_error(ER_NOT_SUPPORTED_YET, MYF(0),
              "LIMIT & IN/ALL/ANY/SOME subquery");
@@ -1551,24 +1552,20 @@ void st_select_lex::print_limit(THD *thd, String *str)
        item->substype() == Item_subselect::IN_SUBS ||
        item->substype() == Item_subselect::ALL_SUBS))
   {
-    DBUG_ASSERT(!item->fixed || select_limit == 1L && offset_limit == 0L);
+    DBUG_ASSERT(!item->fixed ||
+                select_limit->val_int() == LL(1) && offset_limit == 0);
     return;
   }
 
   if (explicit_limit)
   {
     str->append(" limit ", 7);
-    char buff[20];
-    // latin1 is good enough for numbers
-    String st(buff, sizeof(buff),  &my_charset_latin1);
-    st.set((ulonglong)select_limit, &my_charset_latin1);
-    str->append(st);
     if (offset_limit)
     {
+      offset_limit->print(str);
       str->append(',');
-      st.set((ulonglong)select_limit, &my_charset_latin1);
-      str->append(st);
     }
+    select_limit->print(str);
   }
 }
 
@@ -1619,7 +1616,7 @@ bool st_lex::can_be_merged()
           select_lex.with_sum_func == 0 &&
 	  select_lex.table_list.elements >= 1 &&
 	  !(select_lex.options & SELECT_DISTINCT) &&
-          select_lex.select_limit == HA_POS_ERROR);
+          select_lex.select_limit == 0);
 }
 
 
@@ -1756,11 +1753,15 @@ bool st_lex::need_correct_ident()
     values	- SELECT_LEX with initial values for counters
 */
 
-void st_select_lex_unit::set_limit(SELECT_LEX *values)
+void st_select_lex_unit::set_limit(SELECT_LEX *sl)
 {
-  offset_limit_cnt= values->offset_limit;
-  select_limit_cnt= values->select_limit+values->offset_limit;
-  if (select_limit_cnt < values->select_limit)
+  ulonglong select_limit_val;
+
+  select_limit_val= sl->select_limit ? sl->select_limit->val_uint() :
+                                       HA_POS_ERROR;
+  offset_limit_cnt= sl->offset_limit ? sl->offset_limit->val_uint() : ULL(0);
+  select_limit_cnt= select_limit_val + offset_limit_cnt;
+  if (select_limit_cnt < select_limit_val)
     select_limit_cnt= HA_POS_ERROR;		// no limit
 }
 

sql/sql_lex.h

@@ -488,7 +488,7 @@ class st_select_lex: public st_select_lex_node
   List<List_item>     expr_list;
   List<List_item>     when_list;      /* WHEN clause (expression) */
   SQL_LIST *gorder_list;
-  ha_rows select_limit, offset_limit; /* LIMIT clause parameters */
+  Item *select_limit, *offset_limit;  /* LIMIT clause parameters */
   // Arrays of pointers to top elements of all_fields list
   Item **ref_pointer_array;
 

sql/sql_parse.cc

@@ -2351,7 +2351,8 @@ mysql_execute_command(THD *thd)
     {
       SELECT_LEX *param= lex->unit.global_parameters;
       if (!param->explicit_limit)
-	param->select_limit= thd->variables.select_limit;
+	param->select_limit=
+          new Item_int((ulonglong)thd->variables.select_limit);
     }
 
     select_result *result=lex->result;
@@ -3146,13 +3147,15 @@ mysql_execute_command(THD *thd)
     DBUG_ASSERT(first_table == all_tables && first_table != 0);
     if (update_precheck(thd, all_tables))
       break;
+    DBUG_ASSERT(select_lex->offset_limit == 0);
+    unit->set_limit(select_lex);
     res= (result= mysql_update(thd, all_tables,
                                select_lex->item_list,
                                lex->value_list,
                                select_lex->where,
                                select_lex->order_list.elements,
                                (ORDER *) select_lex->order_list.first,
-                               select_lex->select_limit,
+                               unit->select_limit_cnt,
                                lex->duplicates, lex->ignore));
     /* mysql_update return 2 if we need to switch to multi-update */
     if (result != 2)
@@ -3258,9 +3261,11 @@ mysql_execute_command(THD *thd)
     DBUG_ASSERT(first_table == all_tables && first_table != 0);
     if ((res= delete_precheck(thd, all_tables)))
       break;
+    DBUG_ASSERT(select_lex->offset_limit == 0);
+    unit->set_limit(select_lex);
     res = mysql_delete(thd, all_tables, select_lex->where,
                        &select_lex->order_list,
-                       select_lex->select_limit, select_lex->options);
+                       unit->select_limit_cnt, select_lex->options);
     break;
   }
   case SQLCOM_DELETE_MULTI:
@@ -3847,9 +3852,10 @@ mysql_execute_command(THD *thd)
     */
     if (check_db_used(thd, all_tables))
       goto error;
+    unit->set_limit(select_lex);
     res= mysql_ha_read(thd, first_table, lex->ha_read_mode, lex->ident.str,
                        lex->insert_list, lex->ha_rkey_mode, select_lex->where,
-                       select_lex->select_limit, select_lex->offset_limit);
+                       unit->select_limit_cnt, unit->offset_limit_cnt);
     break;
 
   case SQLCOM_BEGIN:
@@ -5130,7 +5136,6 @@ mysql_init_select(LEX *lex)
 {
   SELECT_LEX *select_lex= lex->current_select;
   select_lex->init_select();
-  select_lex->select_limit= HA_POS_ERROR;
   lex->orig_sql_command= SQLCOM_END;
   lex->wild= 0;
   if (select_lex == &lex->select_lex)
@@ -5145,6 +5150,7 @@ bool
 mysql_new_select(LEX *lex, bool move_down)
 {
   SELECT_LEX *select_lex;
+  THD *thd;
   DBUG_ENTER("mysql_new_select");
 
   if (!(select_lex= new(lex->thd->mem_root) SELECT_LEX()))
@@ -5194,7 +5200,7 @@ mysql_new_select(LEX *lex, bool move_down)
       fake->select_number= INT_MAX;
       fake->make_empty_select();
       fake->linkage= GLOBAL_OPTIONS_TYPE;
-      fake->select_limit= HA_POS_ERROR;
+      fake->select_limit= 0;
     }
   }
 
@@ -5242,8 +5248,8 @@ void mysql_init_multi_delete(LEX *lex)
 {
   lex->sql_command=  SQLCOM_DELETE_MULTI;
   mysql_init_select(lex);
-  lex->select_lex.select_limit= lex->unit.select_limit_cnt=
-    HA_POS_ERROR;
+  lex->select_lex.select_limit= 0;
+  lex->unit.select_limit_cnt= HA_POS_ERROR;
   lex->select_lex.table_list.save_and_clear(&lex->auxilliary_table_list);
   lex->lock_option= using_update_log ? TL_READ_NO_INSERT : TL_READ;
   lex->query_tables= 0;
@@ -6757,8 +6763,7 @@ bool multi_update_precheck(THD *thd, TABLE_LIST *tables)
 
   if (select_lex->order_list.elements)
     msg= "ORDER BY";
-  else if (select_lex->select_limit && select_lex->select_limit !=
-	   HA_POS_ERROR)
+  else if (select_lex->select_limit)
     msg= "LIMIT";
   if (msg)
   {

sql/sql_repl.cc

@@ -1316,6 +1316,7 @@ bool mysql_show_binlog_events(THD* thd)
   if (mysql_bin_log.is_open())
   {
     LEX_MASTER_INFO *lex_mi= &thd->lex->mi;
+    SELECT_LEX_UNIT *unit= &thd->lex->unit;
     ha_rows event_count, limit_start, limit_end;
     my_off_t pos = max(BIN_LOG_HEADER_SIZE, lex_mi->pos); // user-friendly
     char search_file_name[FN_REFLEN], *name;
@@ -1324,8 +1325,9 @@ bool mysql_show_binlog_events(THD* thd)
     LOG_INFO linfo;
     Log_event* ev;
 
-    limit_start= thd->lex->current_select->offset_limit;
-    limit_end= thd->lex->current_select->select_limit + limit_start;
+    unit->set_limit(thd->lex->current_select);
+    limit_start= unit->offset_limit_cnt;
+    limit_end= unit->select_limit_cnt;
 
     name= search_file_name;
     if (log_file_name)

sql/sql_select.cc

@@ -10051,7 +10051,7 @@ end_send(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 	{
 	  join->do_send_rows= 0;
 	  if (join->unit->fake_select_lex)
-	    join->unit->fake_select_lex->select_limit= HA_POS_ERROR;
+	    join->unit->fake_select_lex->select_limit= 0;
 	  DBUG_RETURN(NESTED_LOOP_OK);
 	}
       }

sql/sql_union.cc

@@ -448,7 +448,7 @@ bool st_select_lex_unit::exec()
 	  table->no_keyread=1;
 	}
 	res= sl->join->error;
-	offset_limit_cnt= sl->offset_limit;
+	offset_limit_cnt= sl->offset_limit ? sl->offset_limit->val_uint() : 0;
 	if (!res)
 	{
 	  examined_rows+= thd->examined_row_count;

sql/sql_view.cc

@@ -1000,8 +1000,9 @@ bool check_key_in_view(THD *thd, TABLE_LIST *view)
     we do not support updatable UNIONs in VIEW, so we can check just limit of
     LEX::select_lex
   */
-  if ((!view->view && !view->belong_to_view) || thd->lex->sql_command == SQLCOM_INSERT ||
-      thd->lex->select_lex.select_limit == HA_POS_ERROR)
+  if ((!view->view && !view->belong_to_view) ||
+      thd->lex->sql_command == SQLCOM_INSERT ||
+      thd->lex->select_lex.select_limit == 0)
     DBUG_RETURN(FALSE); /* it is normal table or query without LIMIT */
   table= view->table;
   if (view->belong_to_view)

sql/sql_yacc.yy

@@ -721,7 +721,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 	signed_literal now_or_signed_literal opt_escape
 	sp_opt_default
 	simple_ident_nospvar simple_ident_q
-        field_or_var
+        field_or_var limit_option
 
 %type <item_num>
 	NUM_literal
@@ -5542,8 +5542,8 @@ opt_limit_clause_init:
 	{
 	  LEX *lex= Lex;
 	  SELECT_LEX *sel= lex->current_select;
-          sel->offset_limit= 0L;
-          sel->select_limit= HA_POS_ERROR;
+          sel->offset_limit= 0;
+          sel->select_limit= 0;
 	}
 	| limit_clause {}
 	;
@@ -5558,21 +5558,21 @@ limit_clause:
 	;
 
 limit_options:
-	ulong_num
+	limit_option
 	  {
             SELECT_LEX *sel= Select;
             sel->select_limit= $1;
-            sel->offset_limit= 0L;
+            sel->offset_limit= 0;
 	    sel->explicit_limit= 1;
 	  }
-	| ulong_num ',' ulong_num
+	| limit_option ',' limit_option
 	  {
 	    SELECT_LEX *sel= Select;
 	    sel->select_limit= $3;
 	    sel->offset_limit= $1;
 	    sel->explicit_limit= 1;
 	  }
-	| ulong_num OFFSET_SYM ulong_num
+	| limit_option OFFSET_SYM limit_option
 	  {
 	    SELECT_LEX *sel= Select;
 	    sel->select_limit= $1;
@@ -5580,18 +5580,23 @@ limit_options:
 	    sel->explicit_limit= 1;
 	  }
 	;
+limit_option:
+        param_marker
+        | ULONGLONG_NUM { $$= new Item_uint($1.str, $1.length); }
+        | LONG_NUM     { $$= new Item_uint($1.str, $1.length); }
+        | NUM           { $$= new Item_uint($1.str, $1.length); }
 
 
 delete_limit_clause:
 	/* empty */
 	{
 	  LEX *lex=Lex;
-	  lex->current_select->select_limit= HA_POS_ERROR;
+	  lex->current_select->select_limit= 0;
 	}
-	| LIMIT ulonglong_num
+	| LIMIT limit_option
 	{
 	  SELECT_LEX *sel= Select;
-	  sel->select_limit= (ha_rows) $2;
+	  sel->select_limit= $2;
 	  sel->explicit_limit= 1;
 	};
 
@@ -7942,8 +7947,8 @@ handler:
 	  LEX *lex=Lex;
 	  lex->sql_command = SQLCOM_HA_READ;
 	  lex->ha_rkey_mode= HA_READ_KEY_EXACT;	/* Avoid purify warnings */
-	  lex->current_select->select_limit= 1;
-	  lex->current_select->offset_limit= 0L;
+	  lex->current_select->select_limit= new Item_int(1);
+	  lex->current_select->offset_limit= 0;
 	  if (!lex->current_select->add_table_to_list(lex->thd, $2, 0, 0))
 	    YYABORT;
         }