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From Andy Pernsteiner <apernstei...@maprtech.com>
Subject Accessing array index inside JSON
Date Thu, 31 Jul 2014 18:45:09 GMT
Hello, I'm currently attempting to perform queries against a JSON file
which has some nested elements, some of which are arrays.  Here are 2
records worth of the file:


{"trans_id":16,"date":"06/08/2012","time":"07:09:25","user_info":{"cust_id":6,"device":"IOS5","state":"tx"},"marketing_info":{"camp_id":17,"keywords":[]},"trans_info":{"prod_id":[65,1233,182,70,90,12,1520,1563,2144],"purch_flag":"false"}}

{"trans_id":17,"date":"07/31/2013","time":"16:22:26","user_info":{"cust_id":9,"device":"IOS5","state":"oh"},"marketing_info":{"camp_id":1,"keywords":["careful","us","around","you","whatever","i","how"]},"trans_info":{"prod_id":[10,2597,2658,2202,999],"purch_flag":"false"}}



Note that the "prod_id" and "keywords" fields contain arrays.   Here's an
example query without trying to specify the array index:

0: jdbc:drill:> select t.trans_info.prod_id from
dfs.`/myfiles/JSON/mobile.json` t limit 3;

+------------+
|   EXPR$0   |
+------------+
| [1435,673] |
| [785]      |
| [26]       |
+------------+
3 rows selected (0.507 seconds)


So, I can see the array elements just fine, but when I try to access a
specific one I come up w/ nulls:


0: jdbc:drill:> select t.trans_info.prod_id[0] from
`dfs`.`/myfiles/JSON/mobile.json` t limit 10;
+------------+
|   EXPR$0   |
+------------+
| null       |
| null       |
| null       |
| null       |
| null       |
| null       |
| null       |
| null       |
| null       |
| null       |
+------------+
10 rows selected (0.303 seconds)


Am I using the correct notation/subscript syntax here?

Thanks!


-- 
 Andy Pernsteiner
 Manager, Field Enablement
ph: 206.228.0737

www.mapr.com

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