Module: Sequel::SQL::ComplexExpressionMethods

Included in:
LiteralString, GenericExpression, Symbol
Defined in:
lib/sequel/sql.rb

Overview

This module includes other Sequel::SQL::*Methods modules and is included in other classes that are could be either booleans, strings, or numbers. It also adds three methods so that can specify behavior in case one of the operator methods has been overridden (such as Symbol#/).

For example, if Symbol#/ is overridden to produce a string (for example, to make file system path creation easier), the following code will not do what you want:

:price/10 > 100

In that case, you need to do the following:

:price.sql_number/10 > 100

Instance Method Summary collapse

Instance Method Details

#extract(datetime_part) ⇒ Object

Extract a datetime_part (e.g. year, month) from self:

:date.extract(:year) # SQL:  extract(year FROM "date")

Also has the benefit of returning the result as a NumericExpression instead of a generic ComplexExpression.



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# File 'lib/sequel/sql.rb', line 340

def extract(datetime_part)
  Function.new(:extract, PlaceholderLiteralString.new("#{datetime_part} FROM ?", [self])).sql_number
end

#sql_boolean ⇒ Object

Return a BooleanExpression representation of self.



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# File 'lib/sequel/sql.rb', line 345

def sql_boolean
  BooleanExpression.new(:NOOP, self)
end

#sql_number ⇒ Object

Return a NumericExpression representation of self.



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# File 'lib/sequel/sql.rb', line 350

def sql_number
  NumericExpression.new(:NOOP, self)
end

#sql_string ⇒ Object

Return a StringExpression representation of self.



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# File 'lib/sequel/sql.rb', line 355

def sql_string
  StringExpression.new(:NOOP, self)
end