Oracle-选择案例中的动态SQL

INTO 在错误的地方;应该是 EXECUTE IMMEDIATE :

SQL> CREATE OR REPLACE FUNCTION EMPTY_TABLE (table_name IN VARCHAR2)
  2     RETURN NUMBER
  3  IS
  4     Is_empty   NUMBER;
  5     v_SQL      VARCHAR (1000);
  6  BEGIN
  7     v_SQL :=
  8           'SELECT CASE
  9             WHEN EXISTS(SELECT 1 FROM '
 10        || table_name
 11        || ')
 12             THEN  1
 13             ELSE 0
 14           END                               --> not here ...
 15    FROM DUAL';
 16
 17     EXECUTE IMMEDIATE v_SQL INTO Is_empty;  --> ... but here
 18
 19     RETURN Is_empty;
 20  END EMPTY_TABLE;
 21  /

Function created.

SQL> SELECT empty_table ('dept') FROM DUAL;

EMPTY_TABLE('DEPT')
-------------------
                  1

SQL> SELECT empty_table ('dept') FROM DUAL;