How to insert value to table using cursor in stored procedure without getting duplicate records?

问题

I am trying to insert records into existing but empty table based on from date and to date parameters using cursor in stored procedure. Please let me know what I am doing wrong in the below SQL?

When executing this procedure I am getting first row duplicated multiple times.

Error:

Maximum stored procedure, function, trigger or view nesting level exceeded (limit32)

Code:

ALTER proc [dbo].[spempmaster] (@date1 datetime,@date2 datetime)
as
Begin

    Set nocount on

    declare @doj datetime
    declare @empname nchar(10)
    declare @managername nchar(10)
    declare @dept varchar(50)  
    declare emp_report15 cursor for

    select convert(varchar(10),convert(smalldatetime,emp.doj,120),103) DOJ, 
    (emp.name + ' ' + emp.lastname)  Name,
    emp1.name Manager_Name, txtdepartment Department
    from empmaster emp
    left outer join tbljobtitles jt 
        on emp.fkjobtitleid = jt.pkjobtitleid,
    tbldepartment td, 
    tblteam t,
    empmaster emp1
    where
        jt.fkteamid = t.pkteamid
        and td.pkdeptid= t.fkdeptid
        and emp.reportingto = emp1.empno
        and emp.doj between @date1 and @date2
    order by doj

    open emp_report15

    fetch emp_report15 into @doj, @empname, @managername, @dept

    while @@fetch_status = 0
    begin
        insert into tblreport (DOJ,emp_name,manager_name,department)
        values(@doj,@empname,@managername,@dept)
    end

    fetch next from emp_report15 into @doj,@empname,@managername,@dept

    close emp_report15

    deallocate emp_report15

end

回答1:

First of all - there's absolutely no need for a cursor in this situation. SQL Server is a set-based system - don't apply the procedural row-by-agonizing-row approach that works in procedural languages to this set-based system! Use a set-based approach instead!

Also: don't mix the proper ANSI join syntax with the old-style, deprecated comma-separated list of tables JOIN approach. That old style has been deprecated with the SQL-92 standard - more than 20 years ago! - about time to toss it out the window and use the proper ISO/ANSI standard JOIN syntax (INNER JOIN, LEFT OUTER JOIN) all the time.

So basically, in the end - your statement would be something like:

ALTER PROCEDURE [dbo].[spempmaster] (@date1 DATETIME, @date2 DATETIME)
AS 
  INSERT INTO dbo.tblreport(DOJ, emp_name, manager_name, department)
      SELECT 
          CONVERT(VARCHAR(10), CONVERT(SMALLDATETIME, emp.doj, 120), 103), 
          (emp.name + ' ' + emp.lastname),
          emp1.name Manager_Name, 
          txtDepartment 
      FROM 
          dbo.empmaster emp
      INNER JOIN 
          dbo.empmaster emp1 ON emp.reportingto = emp1.empno
      LEFT OUTER JOIN 
         dbo.tbljobtitles jt ON emp.fkjobtitleid = jt.pkjobtitleid
      LEFT OUTER JOIN
         dbo.tblteam t ON jt.fkteamid = t.pkteamid
      LEFT OUTER JOIN    
         dbo.tbldepartment td ON td.pkdeptid = t.fkdeptid
      WHERE
          emp.doj BETWEEN @date1 AND @date2

As for avoiding duplicates: run your SELECT query separately, and see why you're getting duplicates. Just from this code alone, there's no way for outsiders to provide a meaningful answer here - it entirely depends on what data is stored in your tables.

来源：https://stackoverflow.com/questions/20311319/how-to-insert-value-to-table-using-cursor-in-stored-procedure-without-getting-du