Class: Sequel::SQL::StringAgg

Inherits:
GenericExpression show all
Includes:
AliasMethods, CastMethods, InequalityMethods, OrderMethods, PatternMatchMethods, StringConcatenationMethods, StringMethods, SubscriptMethods
Defined in:
lib/sequel/extensions/string_agg.rb

Overview

The StringAgg class represents an aggregate string concatentation.

Defined Under Namespace

Modules: DatasetMethods

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from SubscriptMethods

#sql_subscript

Methods included from PatternMatchMethods

#!~, #=~

Methods included from OrderMethods

#asc, #desc

Methods included from CastMethods

#cast, #cast_numeric, #cast_string

Methods included from AliasMethods

#as

Methods included from StringConcatenationMethods

#+

Methods included from StringMethods

#escaped_ilike, #escaped_like, #ilike, #like

Methods included from IsDistinctFrom::Methods

#is_distinct_from

Methods included from Sequel::SQLite::JSONOpMethods

#sqlite_json_op, #sqlite_jsonb_op

Methods included from Postgres::HStoreOpMethods

#hstore

Methods included from Postgres::RangeOpMethods

#pg_range

Methods included from Postgres::ArrayOpMethods

#pg_array

Methods included from Postgres::JSONOpMethods

#pg_json, #pg_jsonb

Methods included from Postgres::InetOpMethods

#pg_inet

Methods included from Postgres::PGRowOp::ExpressionMethods

#pg_row

Methods included from NumericMethods

#+, #coerce

Methods included from ComplexExpressionMethods

#extract, #sql_boolean, #sql_number, #sql_string

Methods included from BooleanMethods

#~

Methods inherited from Expression

#==, attr_reader, #clone, #eql?, #hash, inherited, #inspect

Constructor Details

#initialize(expr, separator = nil) {|_self| ... } ⇒ StringAgg

Set the expression and separator

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/sequel/extensions/string_agg.rb', line 161

def initialize(expr, separator=nil)
  @expr = expr
  @separator = separator
  yield self if defined?(yield)
  freeze
end

Instance Attribute Details

#expr ⇒ Object (readonly)

The string expression for each row that will concatenated to the output.



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# File 'lib/sequel/extensions/string_agg.rb', line 152

def expr
  @expr
end

#order_expr ⇒ Object (readonly)

The expression that the aggregation is ordered by.



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# File 'lib/sequel/extensions/string_agg.rb', line 158

def order_expr
  @order_expr
end

#separator ⇒ Object (readonly)

The separator between each string expression.



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# File 'lib/sequel/extensions/string_agg.rb', line 155

def separator
  @separator
end

Instance Method Details

#distinct ⇒ Object

Return a modified StringAgg that uses distinct expressions



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# File 'lib/sequel/extensions/string_agg.rb', line 174

def distinct
  self.class.new(@expr, @separator) do |sa|
    sa.instance_variable_set(:@order_expr, @order_expr)
    sa.instance_variable_set(:@distinct, true)
  end
end

#is_distinct? ⇒ Boolean

Whether the current expression uses distinct expressions

Returns:

  • (Boolean) 


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# File 'lib/sequel/extensions/string_agg.rb', line 169

def is_distinct?
  @distinct == true
end

#order(*o) ⇒ Object

Return a modified StringAgg with the given order



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# File 'lib/sequel/extensions/string_agg.rb', line 182

def order(*o)
  self.class.new(@expr, @separator) do |sa|
    sa.instance_variable_set(:@order_expr, o.empty? ? nil : o.freeze)
    sa.instance_variable_set(:@distinct, @distinct)
  end
end