It will returns one column with 1 as result in each row.
1
this query returns one column with all the rows data as 1, for no.of rows present in that table
this query returns one column with all the rows data as 1 for no.of columns present in that table
Hello
'select 1 from tablename ' will show
till no of rows in that particular table
represents the value as result on each row of the table