CreateQuery tab (children 3)
 Identifier tab
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration k (children 1)
    DataType UInt64
   ColumnDeclaration s (children 1)
    DataType String
 Storage definition (children 3)
  Function MergeTree (children 1)
   ExpressionList
  Identifier k
  Set