hive - LATERAL VIEW explode xpath

Question

i have the following input XML:

 <?xml version="1.0"?>
<Employees>
    <Employee emplid="1111">
        <lastname>Watson</lastname>
        <age>30</age>
        <email>johnwatson@sh.com</email>
    </Employee>
    <Employee emplid="2222">
        <firstname>Sherlock</firstname>
        <lastname>Holmes</lastname>
        <age>32</age>
        <email>sherlock@sh.com</email>
    </Employee>
</Employees>

Please notice the firstname missing from the employee 1111

I'm executing following select:

 select 
     c1.emplid,
     fname,
     lname
     from(
     select emplid, xmldata from employeeXML 
     LATERAL VIEW explode (xpath(xmldata,'/Employees/Employee/@emplid')) dummyTable as emplid )c1

     LATERAL VIEW explode (xpath(xmldata,concat('/Employees/Employee[@id="',c1.emplid,'"',']/firstname/text()')))dummyTable2 as fname
     LATERAL VIEW explode (xpath(xmldata,concat('/Employees/Employee[@id="',c1.emplid,'"',']/lastname/text()'))) dummyTable3 
     as lname;

The expected result :

 1111 NULL     Watson
 2222 Sherlock Holmes

Please notice that NULL value for the missing first name)

however i'm getting the following result:

2222 Sherlock Holmes

Becasue the first name is missing for the employee 1111, i'm not getting the first employee back in my query. Is there a way to get both employee data back as indicated in the expected result with first name set to NULL and/or space when it is missing ? Please help. thanks,

score 0 · Answer 1 · answered Dec 11 '13 at 22:07

You can always concatenate the result with an empty string, this should probably be fine:

concat(/Employees/Employee[@id="..."]/firstname/text(), '')

This is not the concatenate you used in hive, but an internal XPath function, so you will probably apply both the XPath and Hive concat in one line.

By the way, I guess you want to use @emplid instead of @id to match your data?

hive - LATERAL VIEW explode xpath

1 Answers1