-Re: Parse MAP viarable Keys in HIVE
Stephen Sprague 2013-07-27, 00:01
not quite sure. you're not happy with the suggestion above?
does the below example work any better for you? ( mytable == the
tablename, myfield == the map column.)
$ hive <<SQL
count(*) as cnt,
from mytable a
lateral view explode(map_keys(a.myfield)) b as tag
On Fri, Jul 26, 2013 at 4:02 PM, R J <[EMAIL PROTECTED]> wrote:
> Many thanks to all.
> The following command returned records like:
> hive>select map_keys(myfield) from mytable;
> hive>select explode(arr) as arr from ( select map_keys(myfield) from
> mytable );
> hive>select explode(arr) as arr ( select map_keys(myfield) from mytable
> ) ;
> Both the above queries give syntax error.
> Is there a sample UDF program that could parse a MAP field in hive?
> *From:* Stephen Sprague <[EMAIL PROTECTED]>
> *To:* [EMAIL PROTECTED]
> *Sent:* Thursday, July 25, 2013 2:01 PM
> *Subject:* Re: Parse MAP viarable Keys in HIVE
> that sure looks like a nice candidate for a UDF, eh? Come to think of it
> i'm surprised there isn't a jar file out there in openSource land that
> contains higher order functions already.
> On Thu, Jul 25, 2013 at 11:20 AM, Arafat, Moiz <[EMAIL PROTECTED]>wrote:
> Try this:
> distinct arr --- Distinct Values
> explode(arr) as arr -- Breaks Array in every column, as separate row .
> map_keys(KV) as arr -- Returns an array of the Key Names for every
> row .
> <table Name>
> ) c
> order by arr;
> On Jul 25, 2013, at 2:08 PM, R J <[EMAIL PROTECTED]> wrote:
> Hi All,
> I have a table in Apache Hive and I am interested in a specific field of
> the table. Table name: Table1 and field name f1. The field f1 is of type
> MAP<string, string>.
> The table is huge. How could I find the distinct key values of the MAP
> variable f1 above?
> I tried:
> $hive -e "select distinct map_keys(f1) from Table1;"
> $hive -e "select k from Table1 LATERAL VIEW explode(f1) et as k,v;"
> Each of the above returned syntax error. Could you please help.
> If the existing values for a few fields of the table ate:
> <x, y>
> <x, p>
> <m, n>
> <m, m>
> <p, q>
> I want the return to be:
> Thanks a lot.