Explain EXPLAIN QUERY TREE (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function sum (children 1)
      ExpressionList (children 1)
       Function if (children 1)
        ExpressionList (children 3)
         Function equals (children 1)
          ExpressionList (children 2)
           Function modulo (children 1)
            ExpressionList (children 2)
             Identifier number
             Literal UInt64_2
           Literal UInt64_0
         Literal UInt64_123
         Literal UInt64_0
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function numbers (children 1)
        ExpressionList (children 1)
         Literal UInt64_100