Why is this Xquery expression returning a null value?
I want to get the maximum value for an attribute. I have the following statement:
let $posts := doc("Posts.xml")/posts/row[./@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
When I want to return maxScore, it shows up as an empty value. Upon further tinkering, the following:
Return $posts/row/@Score
Also shows up as empty, even though I know each row has a 'Score' attribute
I've been fighting with this for over an hour, any help is appreciated
xpath xquery
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
add a comment |
I want to get the maximum value for an attribute. I have the following statement:
let $posts := doc("Posts.xml")/posts/row[./@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
When I want to return maxScore, it shows up as an empty value. Upon further tinkering, the following:
Return $posts/row/@Score
Also shows up as empty, even though I know each row has a 'Score' attribute
I've been fighting with this for over an hour, any help is appreciated
xpath xquery
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
add a comment |
I want to get the maximum value for an attribute. I have the following statement:
let $posts := doc("Posts.xml")/posts/row[./@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
When I want to return maxScore, it shows up as an empty value. Upon further tinkering, the following:
Return $posts/row/@Score
Also shows up as empty, even though I know each row has a 'Score' attribute
I've been fighting with this for over an hour, any help is appreciated
xpath xquery
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
I want to get the maximum value for an attribute. I have the following statement:
let $posts := doc("Posts.xml")/posts/row[./@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
When I want to return maxScore, it shows up as an empty value. Upon further tinkering, the following:
Return $posts/row/@Score
Also shows up as empty, even though I know each row has a 'Score' attribute
I've been fighting with this for over an hour, any help is appreciated
xpath xquery
xpath xquery
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
edited Nov 15 '18 at 3:47
Mads Hansen
44.9k1195122
44.9k1195122
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
asked Nov 14 '18 at 23:59
Francisco José LetterioFrancisco José Letterio
1316
1316
add a comment |
add a comment |
1 Answer
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You are selecting the row elements that meet the criteria of your predicate. So, the $posts variable will have a sequence of row elements.
If you want to select the @Score from each of the row elements in the $posts variable, your XPath should be: $posts/@Score
It would be less confusing if you named the variable $rows.
Or, change the XPath to actually select posts elements:
let $posts := doc("Posts.xml")/posts[row/@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
add a comment |
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1 Answer
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active
oldest
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You are selecting the row elements that meet the criteria of your predicate. So, the $posts variable will have a sequence of row elements.
If you want to select the @Score from each of the row elements in the $posts variable, your XPath should be: $posts/@Score
It would be less confusing if you named the variable $rows.
Or, change the XPath to actually select posts elements:
let $posts := doc("Posts.xml")/posts[row/@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
add a comment |
You are selecting the row elements that meet the criteria of your predicate. So, the $posts variable will have a sequence of row elements.
If you want to select the @Score from each of the row elements in the $posts variable, your XPath should be: $posts/@Score
It would be less confusing if you named the variable $rows.
Or, change the XPath to actually select posts elements:
let $posts := doc("Posts.xml")/posts[row/@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
add a comment |
You are selecting the row elements that meet the criteria of your predicate. So, the $posts variable will have a sequence of row elements.
If you want to select the @Score from each of the row elements in the $posts variable, your XPath should be: $posts/@Score
It would be less confusing if you named the variable $rows.
Or, change the XPath to actually select posts elements:
let $posts := doc("Posts.xml")/posts[row/@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
You are selecting the row elements that meet the criteria of your predicate. So, the $posts variable will have a sequence of row elements.
If you want to select the @Score from each of the row elements in the $posts variable, your XPath should be: $posts/@Score
It would be less confusing if you named the variable $rows.
Or, change the XPath to actually select posts elements:
let $posts := doc("Posts.xml")/posts[row/@OwnerUserId = $user/@Id]
let $maxScore := fn:max(xs:integer($posts/row/@Score))
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
answered Nov 15 '18 at 3:42
Mads HansenMads Hansen
44.9k1195122
44.9k1195122
add a comment |
add a comment |
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