implement expr asin/acos/cot/cos in mysql mode

src/sql/engine/expr/ob_expr_cot.h

@@ -0,0 +1,35 @@
+/**
+ * Copyright 2014-2016 Alibaba Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ *
+ * Authors:
+ *     zimiao<kaizhan.dkz@antgroup.com>
+ */
+#ifndef OCEANBASE_SQL_ENGINE_EXPR_COT_
+#define OCEANBASE_SQL_ENGINE_EXPR_COT_
+#include "sql/engine/expr/ob_expr_operator.h"
+namespace oceanbase
+{
+namespace sql
+{
+class ObExprCot : public ObFuncExprOperator
+{
+public:
+  explicit  ObExprCot(common::ObIAllocator &alloc);
+  virtual   ~ObExprCot();
+  virtual int calc_result_type1(ObExprResType &type,
+                                ObExprResType &radian,
+                                common::ObExprTypeCtx &type_ctx) const;
+  virtual int calc_result1(common::ObObj &result,
+                           const common::ObObj &radian_obj,
+                           common::ObExprCtx &expr_ctx) const;
+private:
+  DISALLOW_COPY_AND_ASSIGN(ObExprCot);
+};
+}
+}
+#endif /* OCEANBASE_SQL_ENGINE_EXPR_COT_ */