SQL to find max value across row and column

SQL to find max value across row and column

drop table t;
create table t(c1 number, c2 number, c3 number);

insert into t values(1,2,3);
insert into t values(4,5,6);
insert into t values(7,8,9);

commit;

select
max(greatest(c1,c2,c3)) col_value
from t;

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with d as (
select 'C1' col_name,max(c1) val from t
union
select 'C2',max(c2) from t
union
select 'C3',max(c3) from t)
select *
from d
where val = (select max(val) from d);

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with d as (select 'C1' col_name,c1 val from t
union
select 'C2',c2 from t
union
select 'C3',c3 from t)
select * from (
select col_name,case when val =  max(val) over() then val end val
from d)
where val is not null;

---------------------------------------------------

select column_name,col_val from (
select column_name,col_val, max(col_val) over() m_val
from t
UNPIVOT (col_val for column_name in (c1,c2,c3)))
where col_val = m_val

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