存储过程在pl/sql中编译时报错：不能做为select/fetch语句的into目标

存储过程如下：
CREATE OR REPLACE PROCEDURE SP_delete_ZYMX_zyd
(
  pDdh varchar2,
  pZYMXRID rowid,
  pZYMXNUM integer
)
is
BEGIN
  delete from zymx where ROWID = pZYMXRID;  select count(*) into pZYMXNUM  from zymx where rdh=pDdh;<--报错:不能做为select/fetch语句的into目标
  IF pZYMXNUM=0 THEN
    delete from zyd where ddh=pDdh;
  END IF;
END;