CreateQuery nullable_key_without_final_mark (children 3)
 Identifier nullable_key_without_final_mark
 Columns definition (children 1)
  ExpressionList (children 1)
   ColumnDeclaration s (children 1)
    DataType Nullable (children 1)
     ExpressionList (children 1)
      DataType String
 Storage definition (children 3)
  Function MergeTree
  Identifier s
  Set
