Explain EXPLAIN SYNTAX (children 1)
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 2)
    ExpressionList (children 1)
     Function uniqTheta (children 1)
      ExpressionList (children 1)
       Function plus (children 1)
        ExpressionList (children 2)
         Identifier x
         Identifier y
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       Subquery (children 1)
        SelectWithUnionQuery (children 1)
         ExpressionList (children 1)
          SelectQuery (children 2)
           ExpressionList (children 2)
            Function modulo (alias x) (children 1)
             ExpressionList (children 2)
              Identifier number
              Literal UInt64_2
            Function modulo (alias y) (children 1)
             ExpressionList (children 2)
              Identifier number
              Literal UInt64_3
           TablesInSelectQuery (children 1)
            TablesInSelectQueryElement (children 1)
             TableExpression (children 1)
              Function numbers (children 1)
               ExpressionList (children 1)
                Literal UInt64_10