Convert These Rows to Columns

Efficiently convert rows to columns in sql server

There are several ways that you can transform data from multiple rows into columns.

Using PIVOT

In SQL Server you can use the PIVOT function to transform the data from rows to columns:

select Firstname, Amount, PostalCode, LastName, AccountNumber
from
(
  select value, columnname
  from yourtable
) d
pivot
(
  max(value)
  for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber)
) piv;

See Demo.

Pivot with unknown number of columnnames

If you have an unknown number of columnnames that you want to transpose, then you can use dynamic SQL:

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT ',' + QUOTENAME(ColumnName) 
                    from yourtable
                    group by ColumnName, id
                    order by id
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = N'SELECT ' + @cols + N' from 
             (
                select value, ColumnName
                from yourtable
            ) x
            pivot 
            (
                max(value)
                for ColumnName in (' + @cols + N')
            ) p '

exec sp_executesql @query;

See Demo.

Using an aggregate function

If you do not want to use the PIVOT function, then you can use an aggregate function with a CASE expression:

select
  max(case when columnname = 'FirstName' then value end) Firstname,
  max(case when columnname = 'Amount' then value end) Amount,
  max(case when columnname = 'PostalCode' then value end) PostalCode,
  max(case when columnname = 'LastName' then value end) LastName,
  max(case when columnname = 'AccountNumber' then value end) AccountNumber
from yourtable

See Demo.

Using multiple joins

This could also be completed using multiple joins, but you will need some column to associate each of the rows which you do not have in your sample data. But the basic syntax would be:

select fn.value as FirstName,
  a.value as Amount,
  pc.value as PostalCode,
  ln.value as LastName,
  an.value as AccountNumber
from yourtable fn
left join yourtable a
  on fn.somecol = a.somecol
  and a.columnname = 'Amount'
left join yourtable pc
  on fn.somecol = pc.somecol
  and pc.columnname = 'PostalCode'
left join yourtable ln
  on fn.somecol = ln.somecol
  and ln.columnname = 'LastName'
left join yourtable an
  on fn.somecol = an.somecol
  and an.columnname = 'AccountNumber'
where fn.columnname = 'Firstname'

Convert the data, split rows into columns in SQL

DECLARE @cols AS NVARCHAR(MAX),
@query AS NVARCHAR(MAX);

SET @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.CountryName)
FROM #temptest c
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'')

set @query = 'SELECT ObjectName, ' + @cols + ' from
(
select ObjectName,CountryName,counts
from #temptest
) x
pivot
(
max(counts)
for CountryName in (' + @cols + ')
) p '

execute(@query)

How to convert row into columns in SQL?

You want to unpivot the data. The challenge is dealing with the datatypes. You need to convert them all to the same type. Presumably, this only applies to amount and perhaps to accountnumber:

select firstName as anyName from t
union all
select cast(Amount as char) from t
union all
select PostalCode from t
union all
select LastName from t
union all
select cast(AccountNumber as char) from t;

If your table is very large or is really a complicated view, then there are other methods that don't require scanning the table once for each column.

You can also use cross join and case:

select (case when n.n = 1 then firstName
             when n.n = 2 then cast(Amount as char)
             when n.n = 3 then PostalCode
             when n.n = 4 then lastName
             when n.n = 5 then cast(AccountNumber as char)
        end) as anyName
from t cross join
    (select 1 as n union all select 2 union all select 3 union all select 4 union all select 5
      ) n

SQL convert rows to columns and flatten

Is this what you want?

select t1.partnum, t2.width, t2.height, t2.depth, count(*) as cnt
from t1 join
     (select t2.orderid,
             sum(case when ccode = 'width' then value end) as width,
             sum(case when ccode = 'height' then value end) as height,
             sum(case when ccode = 'depth' then value end) as depth
      from t2
      group by t2.orderid
     ) t2
     on t2.orderid = t1.orderid
group by t1.partnum, t2.width, t2.height, t2.depth;

I might speculate that you want:

sum(t2.width * t2.height * t2.depth) as area

but the numbers disagree with the values in your question.

Here is a db<>fiddle.

How can I convert these four rows into columns using SQL

Do a GROUP BY. Use case expressions to do conditional aggregation:

select id,
       max(case when Steps = 'Create'   then Steps_Date end) as create_date,
       max(case when Steps = 'Request'  then Steps_Date end) as Request_date,
       max(case when Steps = 'Schedule' then Steps_Date end) as Schedule_date,
       max(case when Steps = 'Complete' then Steps_Date end) as Complete_date
from Steps_table
group by id

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