SQL: unit resolution Item_field not yet accessible [fixes #398]

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

@@ -356,6 +356,12 @@ create or replace table t1 (a int, b int,  key idx(a)) with system versioning;
 insert into t1 values (1, 1), (2, 2);
 select * from t1 where (a, 2) in ((1, 1), (2, 2)) and b = 1;
 a	b
+### Issue #398, NOW is now non-magic
+create or replace table t1 (x int) with system versioning;
+select * from t1 for system_time as of current_timestamp;
+x
+select * from t1 for system_time as of now;
+ERROR 42S22: Unknown column 'now' in 'where clause'
 drop view v1;
 drop table t1, t2;
 call innodb_verify_vtq(32);

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

@@ -242,6 +242,12 @@ create or replace table t1 (a int, b int,  key idx(a)) with system versioning;
 insert into t1 values (1, 1), (2, 2);
 select * from t1 where (a, 2) in ((1, 1), (2, 2)) and b = 1;
 
+--echo ### Issue #398, NOW is now non-magic
+create or replace table t1 (x int) with system versioning;
+select * from t1 for system_time as of current_timestamp;
+--error ER_BAD_FIELD_ERROR
+select * from t1 for system_time as of now;
+
 drop view v1;
 drop table t1, t2;
 

sql/sql_select.cc

@@ -895,6 +895,10 @@ int SELECT_LEX::vers_setup_conds(THD *thd, TABLE_LIST *tables, COND **where_expr
 
     if (vers_conditions)
     {
+      /* TODO: do resolve fix_length_and_dec(), fix_fields(). This requires
+        storing vers_conditions as Item and make some magic related to
+        UNIT_TIMESTAMP/UNIT_TRX_ID at stage of fix_fields()
+        (this is large refactoring). */
       vers_conditions.resolve_units(timestamps_only);
       if (timestamps_only && (vers_conditions.unit_start == UNIT_TRX_ID ||
         vers_conditions.unit_end == UNIT_TRX_ID))

sql/table.cc

@@ -8879,15 +8879,21 @@ void vers_select_conds_t::resolve_units(bool timestamps_only)
   DBUG_ASSERT(start);
   if (unit_start == UNIT_AUTO)
   {
-    unit_start= (!timestamps_only && (start->result_type() == INT_RESULT ||
-      start->result_type() == REAL_RESULT)) ?
-        UNIT_TRX_ID : UNIT_TIMESTAMP;
+    if (start->type() == Item::FIELD_ITEM)
+      unit_start= UNIT_TIMESTAMP;
+    else
+      unit_start= (!timestamps_only && (start->result_type() == INT_RESULT ||
+        start->result_type() == REAL_RESULT)) ?
+          UNIT_TRX_ID : UNIT_TIMESTAMP;
   }
   if (end && unit_end == UNIT_AUTO)
   {
-    unit_end= (!timestamps_only && (end->result_type() == INT_RESULT ||
-      end->result_type() == REAL_RESULT)) ?
-        UNIT_TRX_ID : UNIT_TIMESTAMP;
+    if (start->type() == Item::FIELD_ITEM)
+      unit_start= UNIT_TIMESTAMP;
+    else
+      unit_end= (!timestamps_only && (end->result_type() == INT_RESULT ||
+        end->result_type() == REAL_RESULT)) ?
+          UNIT_TRX_ID : UNIT_TIMESTAMP;
   }
 }