-- 方法1：使用表變量
  -- 聲明表變量
  DECLARE @temp TABLE
  (
      empid INT,
      firstname NVARCHAR(10),
      lastname NVARCHAR(20)
  );
 
 -- 將源表中的數據插入到表變量中
 INSERT INTO @temp(empid, firstname, lastname )
 SELECT empid,firstname,lastname FROM HR.Employees
 ORDER BY empid;
 
 -- 聲明變量
 DECLARE
     @empid AS
 
 INT,
     @firstname AS NVARCHAR(10),
     @lastname AS NVARCHAR(20);
    
 WHILE EXISTS(SELECT empid FROM @temp)
 BEGIN
     -- 也可以使用top 1
     SET ROWCOUNT 1
     SELECT @empid= empid, @firstname= firstname,@lastname= lastname FROM @temp;
     UPDATE HR.Employees SET fullname= @firstname+‘ ‘+@lastname
 
 WHERE empid=@empid;
     SET ROWCOUNT 0
    
     DELETE FROM @temp WHERE empid=@empid;
 END

  -- 方法2：使用臨時表
  -- 創建臨時表
  IF OBJECT_ID(‘tempdb.dbo.#tempemployees‘,‘U‘) IS NOT NULL DROP TABLE dbo.#tempemployees;
  GO
 
  SELECT empid,firstname,lastname
  INTO dbo.#tempemployees
  FROM HR.Employees
  
 
ORDER BY empid;
 
 --SELECT * FROM dbo.#tempemployees;
 
 -- 聲明變量
 DECLARE
     @empid AS INT,
     @firstname AS NVARCHAR(10),
     @lastname AS NVARCHAR(20);
    
 WHILE EXISTS(SELECT empid FROM dbo.#tempemployees)
 BEGIN
     -- 也可以使用top 1
     SET ROWCOUNT 1
     SELECT @empid= empid, @firstname= firstname,@lastname= lastname FROM dbo.#tempemployees;
     UPDATE HR.Employees SET fullname= @firstname+‘ ‘+@lastname WHERE empid=@empid;
     SET ROWCOUNT 0
    
     DELETE FROM dbo.#tempemployees WHERE empid=@empid;
 END

使用表變量或臨時表遍歷數據