CreateQuery test_mtree (children 3)
 Identifier test_mtree
 Columns definition (children 2)
  ExpressionList (children 1)
   ColumnDeclaration x (children 1)
    DataType String
  ExpressionList (children 1)
   Index (children 2)
    Identifier x
    Function set (children 1)
     ExpressionList (children 1)
      Literal UInt64_10
 Storage definition (children 2)
  Function MergeTree
  Function tuple (children 1)
   ExpressionList