SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 2)
    Function sum (alias r1) (children 1)
     ExpressionList (children 1)
      Function arrayElement (children 1)
       ExpressionList (children 2)
        Identifier r
        Literal UInt64_1
    Function sum (alias r2) (children 1)
     ExpressionList (children 1)
      Function arrayElement (children 1)
       ExpressionList (children 2)
        Identifier r
        Literal UInt64_2
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Subquery (children 1)
       SelectWithUnionQuery (children 1)
        ExpressionList (children 1)
         SelectQuery (children 4)
          ExpressionList (children 2)
           Identifier uid
           Function retention (alias r) (children 1)
            ExpressionList (children 2)
             Function equals (children 1)
              ExpressionList (children 2)
               Identifier date
               Literal \'2018-08-06\'
             Function equals (children 1)
              ExpressionList (children 2)
               Identifier date
               Literal \'2018-08-08\'
          TablesInSelectQuery (children 1)
           TablesInSelectQueryElement (children 1)
            TableExpression (children 1)
             TableIdentifier retention_test
          Function in (children 1)
           ExpressionList (children 2)
            Identifier date
            Literal Tuple_(\'2018-08-06\', \'2018-08-08\')
          ExpressionList (children 1)
           Identifier uid