SQL: FOR SYSTEM_TIME support in VIEW expression [fixes #99]

mysql-test/suite/versioning/r/view.result

+create table t1 (x int) with system versioning engine innodb;
+insert into t1 values (1);
+select now(6) into @t1;
+update t1 set x= 2;
+select now(6) into @t2;
+delete from t1;
+set @vt1= concat("create view vt1 as select * from t1 for system_time as of timestamp '", @t1, "'");
+prepare stmt from @vt1;
+execute stmt;
+drop prepare stmt;
+set @vt2= concat("create view vt2 as select * from t1 for system_time as of timestamp '", @t2, "'");
+prepare stmt from @vt2;
+execute stmt;
+drop prepare stmt;
+select * from vt1;
+x
+1
+select * from vt2;
+x
+2
+select * from t1;
+x
+drop view vt1;
+drop view vt2;
+drop table t1;

mysql-test/suite/versioning/t/view.test

+-- source include/have_innodb.inc
+
+create table t1 (x int) with system versioning engine innodb;
+insert into t1 values (1);
+
+select now(6) into @t1;
+update t1 set x= 2;
+
+select now(6) into @t2;
+delete from t1;
+
+set @vt1= concat("create view vt1 as select * from t1 for system_time as of timestamp '", @t1, "'");
+prepare stmt from @vt1; execute stmt; drop prepare stmt;
+
+set @vt2= concat("create view vt2 as select * from t1 for system_time as of timestamp '", @t2, "'");
+prepare stmt from @vt2; execute stmt; drop prepare stmt;
+
+select * from vt1;
+select * from vt2;
+select * from t1;
+
+drop view vt1;
+drop view vt2;
+drop table t1;
+

sql/sql_select.cc

@@ -899,8 +899,6 @@ vers_setup_select(THD *thd, TABLE_LIST *tables, COND **where_expr, SELECT_LEX *s
           *dst_cond= cond1;
         else
           thd->change_item_tree(dst_cond, cond1);
-
-        table->vers_moved_to_where= true;
       }
     } // if (... table->table->versioned())
   } // for (table= tables; ...)
@@ -25036,39 +25034,6 @@ bool mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
   DBUG_RETURN(res || thd->is_error());
 }
 
-void TABLE_LIST::print_system_versioning(THD *thd, table_map eliminated_tables,
-                   String *str, enum_query_type query_type)
-{
-  if (vers_moved_to_where)
-    return;
-
-  DBUG_ASSERT(select_lex);
-  // system versioning
-  if (select_lex->vers_conditions.type != FOR_SYSTEM_TIME_UNSPECIFIED)
-  {
-    switch (select_lex->vers_conditions.type)
-    {
-      case FOR_SYSTEM_TIME_AS_OF:
-        str->append(STRING_WITH_LEN(" for system_time as of "));
-        select_lex->vers_conditions.start->print(str, query_type);
-        break;
-      case FOR_SYSTEM_TIME_FROM_TO:
-        str->append(STRING_WITH_LEN(" for system_time from timestamp "));
-        select_lex->vers_conditions.start->print(str, query_type);
-        str->append(STRING_WITH_LEN(" to "));
-        select_lex->vers_conditions.end->print(str, query_type);
-        break;
-      case FOR_SYSTEM_TIME_BETWEEN:
-        str->append(STRING_WITH_LEN(" for system_time between timestamp "));
-        select_lex->vers_conditions.start->print(str, query_type);
-        str->append(STRING_WITH_LEN(" and "));
-        select_lex->vers_conditions.end->print(str, query_type);
-        break;
-      default:
-        DBUG_ASSERT(0);
-    }
-  }
-}
 
 static void print_table_array(THD *thd, 
                               table_map eliminated_tables,
@@ -25404,8 +25369,6 @@ void TABLE_LIST::print(THD *thd, table_map eliminated_tables, String *str,
       append_identifier(thd, str, t_alias, strlen(t_alias));
     }
 
-    print_system_versioning(thd, eliminated_tables, str, query_type);
-
     if (index_hints)
     {
       List_iterator<Index_hint> it(*index_hints);
@@ -25565,6 +25528,12 @@ void st_select_lex::print(THD *thd, String *str, enum_query_type query_type)
       str->append(having_value != Item::COND_FALSE ? "1" : "0");
   }
 
+  if (vers_conditions.type != FOR_SYSTEM_TIME_UNSPECIFIED)
+  {
+    // versioning conditions must be already unwrapped to WHERE clause
+    str->append(STRING_WITH_LEN(" for system_time all "));
+  }
+
   if (order_list.elements)
   {
     str->append(STRING_WITH_LEN(" order by "));

sql/table.h

@@ -2334,9 +2334,6 @@ struct TABLE_LIST
   TABLE_LIST *first_leaf_for_name_resolution();
   TABLE_LIST *last_leaf_for_name_resolution();
 
-  /* System Versioning */
-  bool vers_moved_to_where;
-
   /**
      @brief
        Find the bottom in the chain of embedded table VIEWs.
@@ -2535,9 +2532,6 @@ struct TABLE_LIST
   void check_pushable_cond_for_table(Item *cond);
   Item *build_pushable_cond_for_table(THD *thd, Item *cond); 
 
-  void print_system_versioning(THD *thd, table_map eliminated_tables,
-                   String *str, enum_query_type query_type);
-
 private:
   bool prep_check_option(THD *thd, uint8 check_opt_type);
   bool prep_where(THD *thd, Item **conds, bool no_where_clause);