每个匹配只显示第一行

Question

我有一个表 (AreaPartners)，我只想匹配每个组中的第一个“名称”记录，按“ID”排序，按“区域”分组。所以对于下表：

    Area    Name            ID
    AB      ISmith          748
    AB      AWood           750
    AB      HArcher         751
    AB      DMunslow        753
    AB      DCornelius      754
    BH      MLee            301
    BH      NMcClean        307
    BH      DMiles          309
    BH      LPayze          325
    BH      MPinnock        329

我想为 AB 返回结果 ISmith，为 BH 返回结果 MLee。

我该怎么做呢？我相信这与 Group By 功能有关，但我一辈子都无法让它发挥作用。

Answer 1

试试这个：

SELECT yourTable.Area, yourTable.Name
FROM yourTable INNER JOIN (
  SELECT MIN(Id) AS MinId
  FROM yourTable
  GROUP BY Area) M ON yourTable.Id = M.MinId

Answer 2

由于注释而更新（没有表变量并且分区结束不是 MS 访问语句）。您也可以使用 IN 声明来做到这一点：

SELECT 
    yourTable.Area, 
    yourTable.Name
FROM yourTable 
WHERE yourTable.Id IN
(
    SELECT 
        MIN(tbl.Id) AS MinId
    FROM 
        yourTable as tbl
    GROUP BY 
        tbl.Area
)

在 MSSQL 中你可以这样写：

DECLARE @tbl TABLE
    (
        Area VARCHAR(100),
        Name VARCHAR(100),
        ID INT
    )
INSERT INTO @tbl
SELECT 'AB','ISmith',748
UNION ALL
SELECT 'AB','AWood',750
UNION ALL
SELECT 'AB','HArcher',751
UNION ALL
SELECT 'AB','DMunslow',753
UNION ALL
SELECT 'AB','DCornelius',754
UNION ALL
SELECT 'BH','MLee',301
UNION ALL
SELECT 'BH','NMcClean',307
UNION ALL
SELECT 'BH','DMiles',309
UNION ALL
SELECT 'BH','LPayze',325
UNION ALL
SELECT 'BH','MPinnock',325
;WITH CTE
AS
(
SELECT
    RANK() OVER(PARTITION BY tbl.Area ORDER BY ID) AS iRank,
    tbl.ID,
    tbl.Area,
    tbl.Name
FROM
    @tbl AS tbl
)
SELECT
    *
FROM
    CTE
WHERE
    CTE.iRank=1