Re: Unable to convert xpath value to date - Mailing list pgsql-general

From David Johnston
Subject Re: Unable to convert xpath value to date
Date
Msg-id 1380805851428-5773223.post@n5.nabble.com
Whole thread Raw
In response to Unable to convert xpath value to date  (saritha N <saritha.0917@gmail.com>)
Responses Re: Unable to convert xpath value to date
List pgsql-general
saritha N wrote
>  ERROR:  invalid value "{0" for "dd"
>  DETAIL:  Value must be an integer.

The leading "{" in the data is the big give away.  This is how a string
representation of an array looks.  From the documentation:

http://www.postgresql.org/docs/9.3/interactive/functions-xml.html


> The function xpath evaluates the XPath expression xpath (a text value)
> against the XML value xml. It returns an array of XML values corresponding
> to the node set produced by the XPath expression. If the XPath expression
> returns a scalar value rather than a node set, a single-element array is
> returned.

If you want to convert the result of an xpath query you need to operate over
an array.  Usually that means unnesting though there are other
possibilities.   If you know you are only dealing (or care about) the first
element you can simply code it as (xpath(...))[1] - note the surrounding
parentheses - to get that first element.

David J.






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