Explain EXPLAIN QUERY TREE (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function tuple (children 1)
      ExpressionList (children 2)
       Function tuple (children 1)
        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
             Function toNullable (children 1)
              ExpressionList (children 1)
               Literal UInt64_0
             Literal UInt64_123
       Function toUInt8 (children 1)
        ExpressionList (children 1)
         Literal UInt64_3
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Function numbers (children 1)
        ExpressionList (children 1)
         Literal UInt64_100
