存储过程输出字符串和游标

Question

大家好，我有一个只输出表格列的存储过程。相反，我希望有 'There are' [column count] 'students'。作为输出。下面的例子。

CREATE OR REPLACE PROCEDURE active_students (arc in out sys_refcursor)
       as
       begin
            open arc for select count(*) from student;
       end;

这会生成

Count(*)
30

希望阅读

There are 30 students.

Answer 1

用途：

CREATE OR REPLACE PROCEDURE JSU4290M.active_students (arc in out sys_refcursor)
AS
BEGIN

  OPEN arc FOR 
  SELECT 'There are '|| COUNT(*) ||' students.' AS col
    FROM STUDENT;

END;

双管道 (||) 是 Oracle（现在是 ANSI 标准）连接字符串的方法。 Oracle 会将整数值隐式转换为字符串。