Merge DAY() system function into opensource branch.

src/sql/engine/expr/ob_expr_day_of_func.cpp

@@ -36,6 +36,12 @@ int ObExprDayOfMonth::calc_dayofmonth(const ObExpr& expr, ObEvalCtx& ctx, ObDatu
   return ObExprTimeBase::calc(expr, ctx, expr_datum, DT_MDAY, true, true);
 }
 
+ObExprDay::ObExprDay(ObIAllocator &alloc)
+    : ObExprTimeBase(alloc, DT_MDAY, T_FUN_SYS_DAY, N_DAY){};
+
+ObExprDay::~ObExprDay()
+{}
+
 ObExprDayOfWeek::ObExprDayOfWeek(ObIAllocator& alloc)
     : ObExprTimeBase(alloc, DT_WDAY, T_FUN_SYS_DAY_OF_WEEK, N_DAY_OF_WEEK){};
 

src/sql/engine/expr/ob_expr_day_of_func.h

@@ -29,6 +29,15 @@ private:
   DISALLOW_COPY_AND_ASSIGN(ObExprDayOfMonth);
 };
 
+class ObExprDay: public ObExprTimeBase {
+public:
+  ObExprDay();
+  explicit ObExprDay(common::ObIAllocator &alloc);
+  virtual ~ObExprDay();
+private:
+  DISALLOW_COPY_AND_ASSIGN(ObExprDay);
+};
+
 class ObExprDayOfWeek : public ObExprTimeBase {
 public:
   ObExprDayOfWeek();

src/sql/engine/expr/ob_expr_operator_factory.cpp

@@ -685,6 +685,7 @@ void ObExprOperatorFactory::register_expr_operators()
   REG_OP(ObExprDegrees);
   REG_OP(ObExprWeightString);
   REG_OP(ObExprBenchmark);
+  REG_OP(ObExprDay);
   // register oracle system function
   REG_OP_ORCL(ObExprSysConnectByPath);
   REG_OP_ORCL(ObExprTimestampNvl);