Select 1

[Akhilesh Trivedi]

What does

select 1 from someTable

do? What is its use ?

[Martin Vashko]

This query creates a cursor which contains one column and as many rows as there are in the table. Value of that column is 1 in all rows.

This is not very useful construct.

I sometimes do use constants in the select clause in more complicated circumstances, eg:
select 'Your table' title, 1 the_order, some_other_value from table1 union all select 'His table', 2, some_other_value from table2 order by 2, 3;
(Note: the order by 2, 3 causes ordering by second and third column of the resultset. It is useful with union operator as there could be ambiguity in column names otherwise.)