Does Ruby Sequel have an equivalent for the SQL "coalesce" function?

Question

In SQL in order to avoid getting a NULL value, I can use the "coalesce" function to substitute it like so:

SELECT COALESCE(some_column, 0) FROM some_table;  

But I can't find any way to do the same thing using Sequel.

Answer 1

DB[:some_table].select{coalesce(some_column, 0)}

Answer 2

An alternative syntax version is Sequel.function(:coalesce,:some_column,5).

Example:

require 'sequel'
Sequel.extension :pretty_table    
DB = Sequel.sqlite
DB.create_table(:mytables){
  primary_key :id
  field :a, :type => :nvarchar, :size => 10
  field :some_column, :type => :fixnum
}

DB[:mytables].insert(:a => 'a1', :some_column => 10)
DB[:mytables].insert(:a => 'a2')

Sequel::PrettyTable.print(
  DB[:mytables].select(:a, :some_column, Sequel.function(:coalesce,:some_column,5))
)

The result:

+--+--------------------------+-----------+
|a |coalesce(`some_column`, 5)|some_column|
+--+--------------------------+-----------+
|a1|                        10|         10|
|a2|                         5|           |
+--+--------------------------+-----------+