Module: Clickhouse::Connection::Query

Included in:
Clickhouse::Connection
Defined in:
lib/clickhouse/connection/query.rb,
lib/clickhouse/connection/query/table.rb,
lib/clickhouse/connection/query/result_row.rb,
lib/clickhouse/connection/query/result_set.rb

Defined Under Namespace

Classes: ResultRow, ResultSet, Table

Instance Method Summary collapse

Instance Method Details

#count(options) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 72

def count(options)
  options = options.merge(:select => "COUNT(*)")
  select_value(options).to_i
end

#create_table(name, &block) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 28

def create_table(name, &block)
  execute(Clickhouse::Connection::Query::Table.new(name, &block).to_sql)
end

#databases ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 20

def databases
  query("SHOW DATABASES").flatten
end

#describe_table(name) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 32

def describe_table(name)
  query("DESCRIBE TABLE #{name}").to_a
end

#drop_table(name) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 43

def drop_table(name)
  execute("DROP TABLE #{name}")
end

#execute(query, body = nil) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 9

def execute(query, body = nil)
  body = post(query, body)
  body.empty? ? true : body
end

#insert_rows(table, options = {}) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 47

def insert_rows(table, options = {})
  options[:csv] ||= begin
    options[:rows] ||= yield([])
    generate_csv options[:rows], options[:names]
  end
  execute("INSERT INTO #{table} FORMAT CSVWithNames", options[:csv])
end

#query(query) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 14

def query(query)
  query = Utils.extract_format(query)[0]
  query += " FORMAT JSONCompact"
  parse_data get(query)
end

#rename_table(*args) ⇒ Object

Raises:



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# File 'lib/clickhouse/connection/query.rb', line 36

def rename_table(*args)
  names = (args[0].is_a?(Hash) ? args[0].to_a : [args]).flatten
  raise Clickhouse::InvalidQueryError, "Odd number of table names" unless (names.size % 2) == 0
  names = Hash[*names].collect{|(from, to)| "#{from} TO #{to}"}
  execute("RENAME TABLE #{names.join(", ")}")
end

#select_row(options) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 59

def select_row(options)
  select_rows(options)[0]
end

#select_rows(options) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 55

def select_rows(options)
  query to_select_query(options)
end

#select_value(options) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 67

def select_value(options)
  values = select_values(options)
  values[0] if values
end

#select_values(options) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 63

def select_values(options)
  select_rows(options).collect{|row| row[0]}
end

#tables ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 24

def tables
  query("SHOW TABLES").flatten
end

#to_select_query(options) ⇒ Object 



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# File 'lib/clickhouse/connection/query.rb', line 77

def to_select_query(options)
  to_select_options(options).collect do |(key, value)|
    next if value.nil? || (value.respond_to?(:empty?) && value.empty?)

    statement = [key.to_s.upcase]
    statement << "BY" if %W(GROUP ORDER).include?(statement[0])
    statement << to_segment(key, value)
    statement.join(" ")

  end.compact.join("\n").force_encoding("UTF-8")
end