sqlserver的listagg

SQL Server 并没有内置的 `LISTAGG` 函数，但可以使用其他方法来实现类似的功能。以下是几种常见的方法：

1. 使用 `FOR XML PATH`：

SELECT 
  Column1,
  STUFF(
    (SELECT ',' + Column2
     FROM YourTable
     WHERE Column1 = t.Column1
     FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 1, '') AS List
FROM YourTable AS t
GROUP BY Column1;

2. 使用递归 CTE：

WITH CTE AS (
  SELECT 
    Column1,
    Column2,
    ROW_NUMBER() OVER (PARTITION BY Column1 ORDER BY Column2) AS rn,
    COUNT(*) OVER (PARTITION BY Column1) AS cnt
  FROM YourTable
)
,RecursiveCTE AS (
  SELECT 
    Column1,
    CAST(Column2 AS NVARCHAR(MAX)) AS List,
    rn,
    cnt
  FROM CTE
  WHERE rn = 1

  UNION ALL

  SELECT 
    c.Column1,
    CAST(rc.List + ',' + c.Column2 AS NVARCHAR(MAX)),
    c.rn,
    c.cnt
  FROM CTE AS c
  INNER JOIN RecursiveCTE AS rc ON c.Column1 = rc.Column1 AND c.rn = rc.rn + 1
)
SELECT 
  Column1,
  MAX(List) AS List
FROM RecursiveCTE
WHERE rn = cnt
GROUP BY Column1;

这些方法可以将每个分组内的多个值合并为一个逗号分隔的字符串。请将 `YourTable` 替换为你要操作的表名，`Column1` 和 `Column2` 替换为相应的列名。