CreateQuery t1 (children 3)
 Identifier t1
 Columns definition (children 1)
  ExpressionList (children 1)
   ColumnDeclaration id (children 1)
    DataType LowCardinality (children 1)
     ExpressionList (children 1)
      DataType Nullable (children 1)
       ExpressionList (children 1)
        DataType Int64
 Storage definition (children 3)
  Function MergeTree
  Identifier id
  Set
