CODEWITHSUNDEEP
xquery
satsamsk
satsamsk

Reputation: 67

How to avoid "invalid lexical value" while adding empty nodes

let $a := <product>
<p1>100</p1>
<p2>100</p2>
<p3/>
</product>
for $i in $a 
return $i/p1 + $i/p2 + $i/p3

Why do i get invalid lexical value here when i expect the sum to be displayed?

Upvotes: 1

Views: 1403

Answers (1)

Leo W&#246;rteler
Leo W&#246;rteler

Reputation: 4241

Your last line return $i/p1 + $i/p2 + $i/p3 is evaluated as return xs:double($i/p1) + xs:double($i/p2) + xs:double($i/p3). This works for p1 and p2, but not p3:

  xs:double($i/p3) = xs:double(<p3/>)
                   = xs:double(xs:untypedAtomic(''))  (: atomization :)
                   = xs:double('')

Since + returns the empty sequence () if one of its arguments is the empty sequence, your approach would not have worked either way. You can use fn:sum($sequence) instead, summing over the text nodes inside the elements:

let $a :=
  <product>
    <p1>100</p1>
    <p2>100</p2>
    <p3/>
  </product>
for $i in $a 
return sum(($i/p1/text(), $i/p2/text(), $i/p3/text()))

The last line can even be shortened to:

return sum($i/(p1, p2, p3)/text())

Upvotes: 2

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