Plsql 使用execute immediate对表行进行计数的查询

编写一个名为

get_total_records

的函数，将表名作为参数传递，并获取表中包含的记录数

---

请使用多个表测试您的函数。

它是哪个数据库？如果是Oracle，这里有一个选项：

SQL> CREATE OR REPLACE FUNCTION get_total_records (par_table_name IN VARCHAR2)
  2     RETURN NUMBER
  3  IS
  4     retval  NUMBER;
  5  BEGIN
  6     EXECUTE IMMEDIATE
  7        'select count(*) from ' || DBMS_ASSERT.sql_object_name (par_table_name)
  8        INTO retval;
  9
 10     RETURN retval;
 11  END;
 12  /

Function created.

SQL> SELECT get_total_records ('emp') result FROM DUAL;

    RESULT
----------
        14

SQL> SELECT get_total_records ('dept') result FROM DUAL;

    RESULT
----------
         4

SQL> SELECT get_total_records ('does_not_exist') result FROM DUAL;
SELECT get_total_records ('does_not_exist') result FROM DUAL
       *
ERROR at line 1:
ORA-44002: invalid object name
ORA-06512: at "SYS.DBMS_ASSERT", line 383
ORA-06512: at "SCOTT.GET_TOTAL_RECORDS", line 6


SQL>

---

它是哪个数据库？如果是Oracle，这里有一个选项：

SQL> CREATE OR REPLACE FUNCTION get_total_records (par_table_name IN VARCHAR2)
  2     RETURN NUMBER
  3  IS
  4     retval  NUMBER;
  5  BEGIN
  6     EXECUTE IMMEDIATE
  7        'select count(*) from ' || DBMS_ASSERT.sql_object_name (par_table_name)
  8        INTO retval;
  9
 10     RETURN retval;
 11  END;
 12  /

Function created.

SQL> SELECT get_total_records ('emp') result FROM DUAL;

    RESULT
----------
        14

SQL> SELECT get_total_records ('dept') result FROM DUAL;

    RESULT
----------
         4

SQL> SELECT get_total_records ('does_not_exist') result FROM DUAL;
SELECT get_total_records ('does_not_exist') result FROM DUAL
       *
ERROR at line 1:
ORA-44002: invalid object name
ORA-06512: at "SYS.DBMS_ASSERT", line 383
ORA-06512: at "SCOTT.GET_TOTAL_RECORDS", line 6


SQL>