How to get rows into columns into SQL Server - sql

Question

I need a small help. I want to convert my result of SQL into single row.
Lets say there is a table Students with ID and Name in it.
if I execute query
select * from Students
it returns.
Col1 Col2
1 Rizwan
2 Ahmed
I want result to be like
1 Rizwan 2 Ahmed
Please note that I want every record in a separate column.
Thanks in advance

Answer 1

I can't think of a plausible scenario where this transform serves any useful purpose because relational-algebra is, by design, about sets of data sharing the same attributes (i.e. tables have rows with columns) - by having everything in a single row with meaningless columns you're just effectively serializing data into a blob.
The only way to achieve this is using Dynamic SQL, as this is the only way to achieve a dynamic number of columns without prior knowledge of what columns are desired.
In MS SQL Server you might think of using PIVOT/UNPIVOT but the columns still need to be manually named, thus requiring Dynamic SQL.
MySQL Server (and MariaDB) have GROUP_CONCAT which can be used to combine multiple rows into a single string (text) value but the server lacks any kind of "split" function. So GROUP_CONCAT doesn't work here because it doesn't return discrete columns.
In T-SQL (MS SQL Server, Sybase) you need to iterate over every target row, this is done using a CURSOR. You cannot reliably perform string concatenation inside a SELECT statment:
DECLARE #sql nvarchar(max) = 'SELECT '
DECLARE c CURSOR FOR
SELECT [Id], [Name] FROM Students ORDER BY [Id] ASC
OPEN c
DECLARE #id int
DECLARE #name nvarchar(100)
FETCH NEXT FROM c INTO #id, #name
WHILE ##FETCH_STATUS = 0
BEGIN
SET #sql = #sql + CONVERT( varchar(10), #id ) + ', ' + #name
FETCH NEXT FROM c INTO #id, #name
END
CLOSE c
DEALLOCATE c
sp_executesql #sql -- this will execute the `SELECT` that was generated, where each discrete value will be returned as an anonymous column.