Question

我想根据两个条件的匹配在表中查找重复的行。第一个条件，匹配“姓氏”字段中的数据。第二个条件，仅匹配FirstName字段中数据的前三个字符。

例如，应选择这两行：

Android Studio

我试图以RedFilter的解决方案为基础：Finding duplicate rows in SQL Server 但返回0条记录。这是我的查询；

synchronize

谢谢

已更新-这似乎可行

LastName       FirstName

 Williams       Robert

 Williams       Robbie

Answer 1

一个选择是仅获取一个COUNT（）并按LastName和FirstName的前3个字符对其进行分区，然后进行过滤。

看看这个：

// this one of the methods which have errors
String __fastcall TAppVersion::GetFileVersion(void)
{
    String Result ;
    BufferPtr = NULL ;

    // Get the product version.
    wsprintf(QueryBlock, "\\StringFileInfo\\%04x%04x\\FileVersion",
                    Array[0].LanguageID, Array[0].CharacterSet);
    VerQueryValue(MemPtr, QueryBlock, &BufferPtr, &BufferLength);

    if(BufferPtr) Result = (char *)BufferPtr;

    return(Result);
}
//---------------------------------------------------
__fastcall TAppVersion::TAppVersion()
{
    FFileName = Application->ExeName ;
    VerSize = GetFileVersionInfoSize(FFileName.c_str(), &VerInfo);
    if (VerSize > 0) {
        MemHandle = GlobalAlloc(GMEM_MOVEABLE, VerSize);
        MemPtr = GlobalLock(MemHandle);
        GetFileVersionInfo(FFileName.c_str(), VerInfo, VerSize, MemPtr);
        VerQueryValue(MemPtr, "\\VarFileInfo\\Translation", &BufferPtr,
                                &BufferLength);
        Array = (TransArray *)BufferPtr;

        FFileVersion = GetFileVersion();
    }
}
//-----------------------------------------------

Answer 2

您可以按LEFT（FirstName，3）进行分组，例如：

    declare @t table (firstName nvarchar(20), lastname nvarchar(20))

    insert into @t
    values ('Robert', 'Williams'), ('Robbie', 'Williams'), ('NotRob', 'Williams'),  ('Steve', 'Other'), ('Steven', 'Other'), ('Someone', 'Else'), ('Roberto', 'Williams')

    select t1.* from @t t1
    cross apply (
            select
                LEFT(firstName, 3) as firstNameShort, lastname
            from
                @t t2
            where LEFT(t2.firstName, 3) = LEFT(t1.firstName, 3)
                and t2.lastname = t1.lastname
            group by
                lastname, LEFT(firstName, 3) 
            having 
                COUNT(*) > 1) t3
    order by t1.lastname, t1.firstName

Answer 3

这是我使用CTE和SUM（）over（）仅获取重复项的方法。

create table #example
(
    LastName varchar(25)      
   ,FirstName varchar(25)
)

INSERT INTO #example
VALUES
     ('Williams','Robert')
    ,('Williams','Robbie')
    ,('Jader','Arruda')
    ,('Jader','Gabriel')

WITH CTE 
AS
(
    SELECT FirstName, LastName,LEFT(FirstName,3) AS First_3_Letter_Name, SUM(1) 
    OVER(PARTITION BY LastName,LEFT(FirstName,3) ORDER BY  
    LastName,LEFT(FirstName,3)) AS ID
    FROM #example
)
SELECT * FROM CTE AS a
WHERE ID > 1;

基于字符匹配在SQL Server中查找重复的行

3 个答案: