Question

我有一个包含memberId的表，但它们不会同时运行。

我该如何循环使用它们？

我有这个：

 select mm.memberid, mm.aspnetuserid, mm.email
 into #MemberIdsToDelete
   from membership.members as mm 
   left join aspnet_membership as asp
     on mm.aspnetuserid=asp.userid 
   left join trade.tradesmen as tr 
     on tr.memberid=mm.memberid  
   where asp.isapproved = 0 and tr.ImportDPN IS NOT NULL and tr.importDPN <> ''
   order by mm.memberid

 ALTER TABLE #MemberIdsToDelete ADD id int NOT NULL AUTO_INCREMENT

 DECLARE @MaxRownum int
 SET @MaxRownum = (SELECT MAX(id) FROM MemberIdsToDelete)

WHILE @Iter <= @MaxRownum
 -- do things
 SET @Iter = @Iter + 1
END

以上不正确，我明显地在alter table行上出错了： 'AUTO_INCREMENT'附近的语法不正确

Answer 1

ALTER TABLE更改实际表格，而不是数据。在您添加数据后添加列没有意义，因此它可能不是您想要的。

您可以使用游标循环遍历任何结果集，但有关游标的两个重要规则：

当您可以进行设定操作时，切勿使用光标。
您可能不需要光标来考虑您正在考虑的事情，重新思考一段时间以确保您需要它。 CURSOR表示您正在考虑SQL问题，因为它是一个程序代码问题 - 它可能是唯一的方法，但要避免它（即使做了其他事情，如果你不这样做，也可以在午餐后回来）。看到设定方法。

在你说你需要从其他表中删除的评论中，这样做会更好：

delete from table1 where memberId in
(
select mm.memberid
   from membership.members as mm 
   left join aspnet_membership as asp
     on mm.aspnetuserid=asp.userid 
   left join trade.tradesmen as tr 
     on tr.memberid=mm.memberid  
   where asp.isapproved = 0 and tr.ImportDPN IS NOT NULL and tr.importDPN <> ''
)
delete from table2 where memberId in
(
select mm.memberid
   from membership.members as mm 
   left join aspnet_membership as asp
     on mm.aspnetuserid=asp.userid 
   left join trade.tradesmen as tr 
     on tr.memberid=mm.memberid  
   where asp.isapproved = 0 and tr.ImportDPN IS NOT NULL and tr.importDPN <> ''
)
delete from table3 where memberId in
(
select mm.memberid
   from membership.members as mm 
   left join aspnet_membership as asp
     on mm.aspnetuserid=asp.userid 
   left join trade.tradesmen as tr 
     on tr.memberid=mm.memberid  
   where asp.isapproved = 0 and tr.ImportDPN IS NOT NULL and tr.importDPN <> ''
)

基于三组的操作本质上更快，查询分析器可以更好地为您进行优化，最重要的是，编写起来更简单。

Answer 2

您可以使用游标循环遍历表格，如下所示：

DECLARE db_cursor CURSOR FOR SELECT Col1, Col2, -- your select query 

OPEN db_cursor
FETCH NEXT FROM db_cursor INTO @Var1, @Var2, -- list of your variables based on select query

WHILE @@FETCH_STATUS = 0   
BEGIN

    -- do stuff

    FETCH NEXT FROM db_cursor INTO @Var1, @Var2, -- list of your variables based on select query
END   

CLOSE db_cursor   
DEALLOCATE db_cursor

Answer 3

也许Row_Number（）更符合您的要求+我刚刚选择了很多对OP的评论：

    SELECT 
        IDENTITY(INT,1,1) AS ID,
        ROW_NUMBER() OVER (ORDER BY mm.memberid) AS RowN,
        mm.memberid,
        mm.aspnetuserid,
        mm.email  
    INTO #MemberIdsToDelete    
    FROM 
        membership.members  mm     
        INNER JOIN aspnet_membership  asp      
            ON mm.aspnetuserid=asp.userid     
        INNER JOIN trade.tradesmen  tr       
            ON tr.memberid=mm.memberid      
    WHERE 
        asp.isapproved <> 0 
        AND tr.importDPN <> ''    


    DECLARE @MaxRownum INT  = (SELECT MAX(RowN) FROM MemberIdsToDelete)  
    DECLARE @Iter INT = 0

    WHILE @Iter <= @MaxRownum  
       -- do things  
        SET @Iter = @Iter + 1 
    END

循环通过表没有全等id

3 个答案: