Explain EXPLAIN QUERY TREE (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function arrayMap (children 1)
      ExpressionList (children 2)
       Function lambda (children 1)
        ExpressionList (children 2)
         Function tuple (children 1)
          ExpressionList (children 1)
           Identifier x
         Function plus (children 1)
          ExpressionList (children 2)
           Identifier x
           Literal UInt64_1
       Literal Array_[UInt64_1, UInt64_2, UInt64_3]
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier test_table