BEGIN
  # 声明自定义变量
  declare c_stgId int;
  declare c_stgName varchar(50);
  # 声明游标结束变量
  declare done INT DEFAULT 0;

  # 声明游标 cr 以及游标读取到结果集最后的处理方式
  declare cr cursor for select Name,StgId from StgSummary limit 3;
  declare continue handler for not found set done = 1;

  # 打开游标
  open cr;

  # 循环
  readLoop:LOOP
    # 获取游标中值并赋值给变量
    fetch cr into c_stgName,c_stgId;
    # 判断游标是否到底，若到底则退出游标
    # 需要注意这个判断
    IF done = 1 THEN
      LEAVE readLoop; 
    END IF; 
    
      SELECT c_stgName,c_stgId;
    
  END LOOP readLoop;
  -- 关闭游标
  close cr;
END

CREATE TEMPORARY TABLE StgSummary(
 Name VARCHAR(50) NOT NULL,
 StgId INT NOT NULL DEFAULT 0
);

ALTER TABLE orig_name RENAME new_name;

DROP TEMPORARY TABLE IF EXISTS StgTempTable;

BEGIN
## 创建临时表
CREATE TEMPORARY TABLE if not exists StgSummary(
 Name VARCHAR(50) NOT NULL,
 StgId INT NOT NULL DEFAULT 0
);
TRUNCATE TABLE StgSummary;

## 新增临时表数据
INSERT INTO StgSummary(Name,StgId)
select '临时数据',1

BEGIN

# 自定义变量
declare c_stgId int;
declare c_stgName varchar(50);
declare done INT DEFAULT 0;

declare cr cursor for select Name,StgId from StgSummary ORDER BY StgId desc LIMIT 3;
declare continue handler for not found set done = 1;

-- 打开游标
open cr;
testLoop:LOOP
	-- 获取结果
	fetch cr into c_stgName,c_stgId;
	IF done = 1 THEN
		LEAVE testLoop; 
	END IF; 
	
  
  SELECT c_stgName,c_stgId;
	
END LOOP testLoop;
-- 关闭游标
close cr;

End;
DROP TEMPORARY TABLE IF EXISTS StgSummary;
End;