帶有 Group By 子句的 SQL 逗號分隔行

Question

我有以下查詢：

SELECT
  Account,
  Unit,
  SUM(state_fee),
  Code
FROM tblMta
WHERE MTA.Id = '123'
GROUP BY Account,Unit

這當然會引發異常，因為 Code 不在group by子句中。 每個 state_fee 都有一個代碼。 如何讓此代碼顯示在 1 條記錄中（每個 state_fee 1 個代碼，每個單元有多個 state_fee）作為逗號分隔的列表？ 我在這里查看了不同的解決方案，但找不到任何與group by合作的解決方案。

Answer 1

您想使用FOR XML PATH構造：

SELECT ACCOUNT, 
       unit, 
       SUM(state_fee), 
       Stuff((SELECT ', ' + code 
              FROM   tblmta t2 
              WHERE  t2.ACCOUNT = t1.ACCOUNT 
                     AND t2.unit = t1.unit 
                     AND t2.id = '123' 
              FOR XML PATH('')), 1, 2, '') [Codes] 
FROM   tblmta t1 
WHERE  t1.id = '123' 
GROUP  BY ACCOUNT, 
          unit 

在此處查看其他示例：

• 兩個表之間的 SQL 相同單元需要 1 個單元格中的訂單號
• SQL Query 以逗號分隔符以及 SQL Server 中的按列分組獲取聚合結果

Answer 2

這將顯示表、索引名稱、索引類型、索引列和包含的列：

with [indexes] (table_name, index_name, column_name, index_id, key_ordinal, object_id, type_desc)
as(
SELECT  distinct
  T.[name] AS [table_name], I.[name] AS [index_name], 
  AC.[name] AS [column_name],
  I.[index_id], IC.[key_ordinal], T.[object_id], i.type_desc
FROM sys.[tables] AS T  
  INNER JOIN sys.[indexes] I ON T.[object_id] = I.[object_id]  
  INNER JOIN sys.[index_columns] IC ON I.[object_id] = IC.[object_id]  and IC.index_id=I.index_id
  LEFT OUTER JOIN sys.[all_columns] AC ON T.[object_id] = AC.[object_id] AND IC.[column_id] = AC.[column_id] 
WHERE T.[is_ms_shipped] = 0 AND I.[type_desc] <> 'HEAP'
)
select
    distinct
    db_name() as dbname,
    type_desc,
    table_name,
    index_name,
    column_name,
    STUFF((
        select ', ' + column_name
        from [indexes] t2
        where t1.table_name=t2.table_name and t1.[index_name]=t2.[index_name] and t2.[key_ordinal] = 0
        for xml path('')), 1, 2, '') inc_cols
from [indexes] t1
where t1.[key_ordinal] = 1
GROUP BY table_name, index_name, type_desc, column_name

Answer 3

在 SQL Server 2017 (14.x) 及更高版本中，您可以使用 STRING_AGG 函數：

https://docs.microsoft.com/en-us/sql/t-sql/functions/string-agg-transact-sql?view=sql-server-ver16

SELECT
  Account,
  Unit,
  SUM(state_fee),
  STRING_AGG(Code, ',')
FROM tblMta
WHERE MTA.Id = '123'
GROUP BY Account,Unit

根據代碼的數據類型，您可能需要對其進行轉換：

SELECT
  Account,
  Unit,
  SUM(state_fee),
  STRING_AGG(CONVERT(NVARCHAR(max), Code), ',')
FROM tblMta
WHERE MTA.Id = '123'
GROUP BY Account,Unit

Answer 4

沒有用於連接的內置聚合函數，但本文討論了幾種替代解決方案，包括用戶定義的連接聚合函數：

https://www.simple-talk.com/sql/t-sql-programming/concatenating-row-values-in-transact-sql/