CreateQuery tab (children 4)
 Identifier tab
 Columns definition (children 2)
  ExpressionList (children 2)
   ColumnDeclaration col1 (children 1)
    DataType String
   ColumnDeclaration col2 (children 1)
    DataType String
  ExpressionList (children 1)
   Index (children 2)
    Identifier col2
    Function set (children 1)
     ExpressionList (children 1)
      Literal UInt64_0
 Storage definition (children 2)
  Function MergeTree (children 1)
   ExpressionList
  Identifier col1
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 1)
    ExpressionList (children 2)
     Literal \'v1\'
     Literal \'v2\'
