CreateQuery t_vertical_merges (children 3)
 Identifier t_vertical_merges
 Columns definition (children 1)
  ExpressionList (children 2)
   ColumnDeclaration a (children 1)
    DataType Nullable (children 1)
     ExpressionList (children 1)
      DataType String
   ColumnDeclaration b (children 1)
    DataType Int8
 Storage definition (children 3)
  Function MergeTree
  Function tuple (children 1)
   ExpressionList
  Set
