CreateQuery array_union (children 3)
 Identifier array_union
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration date (children 1)
    DataType Date
   ColumnDeclaration arr (children 1)
    DataType Array (children 1)
     ExpressionList (children 1)
      DataType UInt8
 Storage definition (children 3)
  Function MergeTree
  Identifier date
  Identifier date