module Sequel::SQL::NumericMethods

  1. lib/sequel/sql.rb

This module includes the standard mathematical methods (+, -, *, and /) that are defined on objects that can be used in a numeric context in SQL (Symbol, LiteralString, and SQL::GenericExpression).

Sequel[:a] + :b # "a" + "b"
Sequel[:a] - :b # "a" - "b"
Sequel[:a] * :b # "a" * "b"
Sequel[:a] / :b # "a" / "b"

One exception to this is if + is called with a String or StringExpression, in which case the || operator is used instead of the + operator:

Sequel[:a] + 'b' # "a" || 'b'

Methods

Public Instance

  1. +
  2. coerce

Public Instance methods

+ (ce)

Use || as the operator when called with StringExpression and String instances, and the + operator for LiteralStrings and all other types.

[show source]
    # File lib/sequel/sql.rb
798 def +(ce)
799   case ce
800   when LiteralString
801     NumericExpression.new(:+, self, ce)
802   when StringExpression, String
803     StringExpression.new(:'||', self, ce)
804   else
805     NumericExpression.new(:+, self, ce)
806   end
807 end
coerce (other)

If the argument given is Numeric, treat it as a NumericExpression, allowing code such as:

1 + Sequel[:x] # SQL: (1 + x)
Sequel.expr{1 - x(y)} # SQL: (1 - x(y))
[show source]
    # File lib/sequel/sql.rb
788 def coerce(other)
789   if other.is_a?(Numeric)
790     [SQL::NumericExpression.new(:NOOP, other), self]
791   else
792     super 
793   end
794 end