Module: ArelExtensions::NullFunctions

Included in:
Arel::Nodes::Function, Arel::Nodes::Grouping, Attributes, ArelExtensions::Nodes::Case
Defined in:
lib/arel_extensions/null_functions.rb

Instance Method Summary collapse

Instance Method Details

#coalesce(*args) ⇒ Object

returns the first non-null expr in the expression list. You must specify at least two expressions. If all occurrences of expr evaluate to null, then the function returns null.



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# File 'lib/arel_extensions/null_functions.rb', line 24

def coalesce *args
  args.unshift(self)
  ArelExtensions::Nodes::Coalesce.new args
end

#coalesce_blank(*args) ⇒ Object 



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# File 'lib/arel_extensions/null_functions.rb', line 29

def coalesce_blank *args
  res = Arel.when(self.cast(:string).present).then(self)
  args[0...-1].each do |a|
    val = a.is_a?(Arel::Nodes::Node) ? a : Arel.quoted(a)
    res = res.when(val.present).then(a)
  end
  res = res.else(args[-1])
  res
end

#if_present ⇒ Object

if_present returns nil if the the value is nil or blank



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# File 'lib/arel_extensions/null_functions.rb', line 8

def if_present
  Arel.when(self.cast(:string).present).then(self)
end

#is_not_null ⇒ Object

ISNOTNULL function lets you return an alternative value when an expression is NOT NULL.



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# File 'lib/arel_extensions/null_functions.rb', line 18

def is_not_null
  ArelExtensions::Nodes::IsNotNull.new [self]
end

#is_null ⇒ Object

ISNULL function lets you return an alternative value when an expression is NULL.



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# File 'lib/arel_extensions/null_functions.rb', line 13

def is_null
  ArelExtensions::Nodes::IsNull.new [self]
end