Question

使用SQL Server 2000，考虑具有超过400,000条记录的源表。

任务是选择每个regno条目，其中包含具有重复项或多个条目的动态递增rowid或序列号。对于那些在源表中没有重复条目的人，rowid应该只是null。

以下是所需输出的示例：

    regno   rowid
    100      1
    100      2
    100      3
    200      null
    300      4
    300      5
    400      null
    500      null
    600      6
    600      7

问题： 在SQL Server 2000中使用TSQL进行所需序列递增的查询是什么？

Answer 1

如果我的评论是正确的（600应该是6,7），那么看看这个

DECLARE @Table TABLE(
        regno INT,
        rowid INT
)

INSERT INTO @Table (regno,rowid) SELECT 100, NULL
INSERT INTO @Table (regno,rowid) SELECT 100, NULL
INSERT INTO @Table (regno,rowid) SELECT 100, NULL
INSERT INTO @Table (regno,rowid) SELECT 200, NULL
INSERT INTO @Table (regno,rowid) SELECT 300, NULL
INSERT INTO @Table (regno,rowid) SELECT 300, NULL
INSERT INTO @Table (regno,rowid) SELECT 400, NULL
INSERT INTO @Table (regno,rowid) SELECT 500, NULL
INSERT INTO @Table (regno,rowid) SELECT 600, NULL
INSERT INTO @Table (regno,rowid) SELECT 600, NULL

DECLARE @TempTable TABLE(
        ID INT IDENTITY(1,1),
        regno INT
)

INSERT INTO @TempTable (regno)
SELECT  regno
FROM    @Table

SELECT  regno,
        CASE 
            WHEN (SELECT COUNT(1) FROM @TempTable WHERE regno = t.regno) = 1 
                THEN NULL 
            ELSE (SELECT COUNT(1) FROM @TempTable WHERE regno = t.regno) - (SELECT COUNT(1) FROM @TempTable WHERE regno = t.regno AND ID > t.ID) +
            (SELECT COUNT(1) FROM @TempTable WHERE regno < t.regno AND regno IN (SELECT regno FROM @TempTable GROUP BY regno having COUNT(1) > 1))
        END Val     
FROM    @TempTable t

Answer 2

提取非唯一记录的查询将是

select regno,count(*) from table group by regno having count(*) > 1

我不太了解MSSQL如何生成递增序列号来更新与查询匹配的记录。

Answer 3

没有临时表：

DECLARE @Table TABLE(
        regno INT
)

INSERT INTO @Table (regno) SELECT 100
INSERT INTO @Table (regno) SELECT 100
INSERT INTO @Table (regno) SELECT 100
INSERT INTO @Table (regno) SELECT 200
INSERT INTO @Table (regno) SELECT 300
INSERT INTO @Table (regno) SELECT 300
INSERT INTO @Table (regno) SELECT 400
INSERT INTO @Table (regno) SELECT 500
INSERT INTO @Table (regno) SELECT 600
INSERT INTO @Table (regno) SELECT 600

select regno, null as rowid from @Table group by regno having count(*) = 1
union 
select regno, row_number() OVER (ORDER BY a.regno) as rowid
   from @table a
   where regno in (select regno from @table group by regno having count(*) > 1)

regno       rowid
----------- --------------------
100         1
100         2
100         3
200         NULL
300         4
300         5
400         NULL
500         NULL
600         6
600         7

糟糕 - 在发布此内容之前，没有看到您想在SQL 2000中执行此操作...请忽略我的查询。在SQL 2000中，您需要一个临时表来生成序列。

TSQL-为重复记录生成序列号

3 个答案: