Sqlserver to Mysql conversion - sys table id

Question

I have the following query in SQL Server:

Declare @val Varchar(max)
Select @val = COALESCE(@val + ', ' + col.name, col.name)
FROM sys.objects AS obj 
INNER JOIN sys.columns AS col ON col.object_id = obj.object_id 
INNER JOIN sys.index_columns AS idx_cols ON idx_cols.column_id = col.column_id 
AND idx_cols.object_id = col.object_id 
INNER JOIN sys.indexes AS idx ON idx_cols.index_id = idx.index_id AND idx.object_id = col.object_id
WHERE (obj.name = 'NOME_TABELA' ) AND (idx.is_unique = 1) 
if @val is null 
    Select @val = COALESCE(@val + ', ' + COLUMN_NAME, COLUMN_NAME) 
    from information_schema.columns 
    where table_name = 'NOME_TABELA' 
    order by ORDINAL_POSITION
Select @val varColumnsOrder

Some fields do not exist in Mysql (like id of some tables sys.objects), how would you transform this first function into Mysql? Since the first function the relevance is to seek by following the id.