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

1

1

1

1

1

till no of rows in that particular table

represents the value as result on each row of the table