SQL - Select the largest value within a row - sql

Question

I seem to be stuck on this and can't find a solution having had a look around.
I have an SQL table who's first row looks something like this:
Name Val1 Val2 Val3
John 1000 2000 3000
What I need to do is Select the largest value within this row i.e. 3000
Obviously if these values were in a column rather than row you could just use SELECT MAX(column) FROM table to get the largest value in the column. Is there an equivalent of this for finding the max value in a row?
I have also had a look at the uses of PIVOT and UNPIVOT but I don't think they are useful to me here..
The only way I have been able to do it is to create a temp table and insert each value into a single column like so:
CREATE TABLE #temp (colvals float)
INSERT INTO #temp (colvals)
SELECT Val1 FROM table WHERE ID=1
UNION
SELECT Val2 FROM table WHERE ID=1
UNION
SELECT Val3 FROM table WHERE ID=1
--------------------------------------------
SELECT MAX(colvals) FROM #temp
--------------------------------------------
DROP TABLE #temp
However I feel this is rather slow especially as my table has a lot more columns than the snippet I have shown above.
Any ideas?
Thanks in advance.

Answer 1

You can build a reference table for columns by APPLY and use native MAX()
-- Sample Data
declare #data table (Name varchar(10), Val1 int, Val2 int, Val3 int, Val4 int, Val5 int, Val6 int)
insert #data values
('John', 1000, 2000, 3000, 4000, 5000, 6000),
('Mary', 1, 2, 3, 4, 5, 6)
select Name, MaxValue from
#data
cross apply
(
select max(value) as MaxValue
from
(values
(Val1),(Val2),(Val3),(Val4),(Val5),(Val6) -- Append here
) t(value)
) result
SQL Fiddle

Answer 2

select MAX(case when c1 > c2 and c1 > c3 then c1
when c2 > c3 then c2
else c3
end)
from tablename

Answer 3

You need something like this:
SELECT *, Row_Number() OVER (ORDER BY GETDATE()) Rowid INTO #temp From yourtable
DECLARE #Columns AS Varchar(MAX)
SET #Columns =''
SELECT #Columns = #Columns + ',[' + name + ']' FROM tempdb..syscolumns
WHERE id=object_id('tempdb..#temp') AND name <> 'Rowid'
SELECT #Columns = Right(#Columns, len(#Columns)-1)
exec ('Select Rowid,Max(val) maxval from #temp t Unpivot(val For data in (' + #Columns + ')) as Upvt Group by Rid')
Drop table #temp

Answer 4

Use math logic:
select
case
when val1 >= val2 and val1 >= val2 then val1
when val2 >= val1 and val2 >= val3 then val2
else val3
end maxVal
from mytable
where id = 1

Answer 5

I think you were on the right track when you looked at unpivot as an option. Becaue that's exactly what you want to do - you have a pivot table, and you want the unpivoted value from it. Here's what I came up with:
declare #base table (Name char(4), Val1 int, Val2 int ,Val3 int);
insert into #base (Name, Val1 , Val2 , Val3) values ('John' , 1000 , 2000 , 3000);
select name, max(value) as max_value
from (
select name, valuetype, value
from #base b
unpivot ( value for valuetype in (Val1 , Val2 , Val3)) as u
) as up
group by name
To expand to your whole table, you can then just add more column names to the unpivot row:
unpivot ( value for valuetype in (Val1 , Val2 , Val3, ... more values here...)) as u

Answer 6

You could always replicate this answer Is there a Max function in SQL Server that takes two values like Math.Max in .NET?
-- Sample Data
declare #data table (Name varchar(10), Val1 int, Val2 int, Val3 int, Val4 int, Val5 int, Val6 int)
insert #data values
('John', 1000, 2000, 3000, 4000, 5000, 6000),
('Mary', 1, 2, 3, 4, 5, 6),
('Tony66', 1, 2, 3, 4, 5, 66),
('Tony55', 1, 2, 3, 4, 55, 6),
('Tony44', 1, 2, 3, 44, 5, 6),
('Tony33', 1, 2, 33, 4, 5, 6),
('Tony22', 1, 22, 3, 4, 5, 6),
('Tony11', 11, 2, 3, 4, 5, 6)
SELECT name,
(SELECT MAX(value)
FROM (VALUES (Val1),(Val2), (Val3), (Val4), (Val5), (Val6)) AS AllValues(value)) AS 'MaxValue'
FROM #data