Question

我想根据行（行号）获取记录。我已经完成了使用sql查询本身。

select * from (select m.*,rownum r from employees m) where r between 80 and 100

但是现在我想在存储过程（oracle）中使用游标来获取相同的东西来获取80和100之间的记录（基于rownum伪列）。任何人都可以帮助我吗？

Answer 1

您可能需要查看Stored Procedures和Cursors才能了解基本知识。除此之外，您的查询可以很容易地包含在游标和过程中。如果您打算使用显式游标，它可能是这样的：

CREATE OR REPLACE stored_procedure_name AS
CURSOR IS
  select * from (select rownum r,salary from employees) where r between 80 and 100;

BEGIN
 open c1; 
 loop 
   fetch c1 
   into a,b; 
   dbms_output.put_line(a || b); 
   exit when c1%notfound; 
 end loop;
 close c1;
END;

Answer 2

您可以使用简化的语法，避免直接处理游标。我认为这种方式不易出错。

示例：

begin
  for rec in (
    select rn, salary
    from (
      select rownum as rn, salary
      from employees
    ) where rn between 80 and 100
  ) loop
    dbms_output.put_line(to_char(rec.rn) || rec.salary);
  end loop;
end;
/

文档：Query Result Set Processing With Cursor FOR LOOP Statements

修改

这种结构的一般形式是：

begin for rec in ( select * from employees -- write any SQL you want here ) loop -- do whatever you need to do inside the loop... -- you can access the results of the query through the "rec" variable. dbms_output.put_line(rec.column1); dbms_output.put_line(rec.column2); dbms_output.put_line(rec.column3); end loop; end; /

Answer 3

您可以使用像bellow

这样的简单构造

declare
  v_e_row  employees%rowtype; --employees table row type
  v_rownum number;
begin
  for emp in (select * from (select m.* , rownum r from employees m) where r between 80 and 100) 
    loop
      v_e_row.emp_id  := emp.emp_id; -- sample value ( you will get all value including rownum)
      v_rownum := emp.r;
      dbms_output.put_line(v_e_row.emp_id||v_rownum); 
    end loop;
end;

oracle中的存储过程，用于根据行获取记录

3 个答案: