Explain EXPLAIN QUERY TREE (children 2)
 Set
 SelectWithUnionQuery (children 1)
  ExpressionList (children 1)
   SelectQuery (children 3)
    ExpressionList (children 1)
     Asterisk
    TablesInSelectQuery (children 1)
     TablesInSelectQueryElement (children 1)
      TableExpression (children 1)
       TableIdentifier x
    Function or (children 1)
     ExpressionList (children 2)
      Function and (children 1)
       ExpressionList (children 2)
        Identifier C
        Identifier E
      Function and (children 1)
       ExpressionList (children 2)
        Function and (children 1)
         ExpressionList (children 2)
          Identifier C
          Identifier E
        Function and (children 1)
         ExpressionList (children 2)
          Identifier C
          Identifier E
