let
tab = #table(
{ "id", "grp", "val a", "val b"},
{
{ 1 , "x" , "ABC" , 1.3 },
{ 2 , "y" , "DEF" , 4.0 },
{ 3 , "z" , "FGH" , 2.7 }
}),
tab_ = Table.TransformColumnNames(tab, each Text.Upper(_))
in
tab_
Table.RenameColumns