Page 88 - SQL

SQL Server 2016 and earlier

(CTE included to encourage the DRY principle)

WITH CTE_TableName AS (
SELECT ColumnA, ColumnB
FROM TableName)
SELECT t0.ColumnA
, STUFF((
SELECT ',' + t1.ColumnB
FROM CTE_TableName t1
WHERE t1.ColumnA = t0.ColumnA
ORDER BY t1.ColumnB
FOR XML PATH('')), 1, 1, '') AS ColumnBs
FROM CTE_TableName t0
GROUP BY t0.ColumnA
ORDER BY ColumnA;

SQL Server 2017 and SQL Azure

SELECT ColumnA
, STRING_AGG(ColumnB, ',') WITHIN GROUP (ORDER BY ColumnB) AS ColumnBs
FROM TableName
GROUP BY ColumnA
ORDER BY ColumnA;

SQLite

without ordering:

SELECT ColumnA
, GROUP_CONCAT(ColumnB, ',') AS ColumnBs
FROM TableName
GROUP BY ColumnA
ORDER BY ColumnA;

ordering requires a subquery or CTE:

WITH CTE_TableName AS (
SELECT ColumnA, ColumnB
FROM TableName
ORDER BY ColumnA, ColumnB)
SELECT ColumnA
, GROUP_CONCAT(ColumnB, ',') AS ColumnBs
FROM CTE_TableName
GROUP BY ColumnA
ORDER BY ColumnA;

Count

https://riptutorial.com/ 70