SQL comma-separated row with Group By clause - sql

Question

I have the following query:
SELECT
Account,
Unit,
SUM(state_fee),
Code
FROM tblMta
WHERE MTA.Id = '123'
GROUP BY Account,Unit
This of course throws an exception because the Code is not in the group by clause. Each state_fee has a code. How do I get this code to display in 1 record (1 code per state_fee which is multiple state_fee per unit) as a comma-separated list? I looked into different solutions on here but I couldn't find any that worked with a group by.

Answer 1

You want to use FOR XML PATH construct:
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
See other examples here:
SQL same unit between two tables needs order numbers in 1 cell
SQL Query to get aggregated result in comma seperators along with group by column in SQL Server

Answer 2

There is no built-in aggregate function to concatenate, but this article discusses several alternative solutions, including a user-defined concatenate aggregate function:
https://www.simple-talk.com/sql/t-sql-programming/concatenating-row-values-in-transact-sql/

Answer 3

This will show you the table, index name, index type, indexed columns, and included columns:
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 4

In SQL Server 2017 (14.x) and later you can use the STRING_AGG function:
https://learn.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
Depending on the data type of Code you might need to convert it:
SELECT
Account,
Unit,
SUM(state_fee),
STRING_AGG(CONVERT(NVARCHAR(max), Code), ',')
FROM tblMta
WHERE MTA.Id = '123'
GROUP BY Account,Unit