ORA-06550 & PLS-00103: 遇到符号 "drop"

ORA-06550 & PLS-00103 : Encountered the symbol "drop"

这是怎么回事?

DECLARE
  V_COUNT NUMBER(10) := 0;
BEGIN

  SELECT COUNT(*) INTO V_COUNT FROM USER_VIEWS WHERE VIEW_NAME = 'DBO$EVT_APP';

  IF V_COUNT > 0 THEN
    DROP VIEW DBO$EVT_APP;
  END IF;

END;

我收到以下错误:

Error report:
ORA-06550: line 9, column 5:
PLS-00103: Encountered the symbol "DROP" when expecting one of the following: ...

这对我来说似乎有效 SQL。这是我的确切代码,已粘贴。

DECLARE
  V_COUNT NUMBER(10) := 0;

    BEGIN

      SELECT COUNT(*) INTO V_COUNT FROM USER_VIEWS WHERE VIEW_NAME = 'DBO$EVT_APP';

      IF V_COUNT > 0 THEN
        execute immediate 'DROP VIEW DBO$EVT_APP';
      END IF;

    END;