I think I figured out. I can get map keys as an array then use concat_ws(string SEP, array<string>) to convert the array to a string, then I can use instr(string str, string substr) to test if a substring exists or not.
From: Szehon Ho [mailto:sze...@cloudera.com] Sent: Tuesday, March 18, 2014 2:08 AM To: user@hive.apache.org Subject: Re: read a Hive Map without knowing keys You can try to check other string udf's for that case, here https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF , they will be in the section on string functions. Thanks Szehon On Mon, Mar 17, 2014 at 5:06 PM, Frank Luo <j...@merkleinc.com<mailto:j...@merkleinc.com>> wrote: That is helpful, Thx! More dumb questions. What is "select *?" ? Also, any hints on how to find whether the map_keys contains a substring? For example, supposing the map_keys contains emails, I want to see if one of the emails contains "gmail.com<http://gmail.com>". From: Szehon Ho [mailto:sze...@cloudera.com<mailto:sze...@cloudera.com>] Sent: Monday, March 17, 2014 5:14 PM To: user@hive.apache.org<mailto:user@hive.apache.org> Subject: Re: read a Hive Map without knowing keys Select *? There are other built-in functions like map_keys and map_values you can use in queries on maps. Not sure if this addresses the question. Thanks Szehon On Mon, Mar 17, 2014 at 3:05 PM, Frank Luo <j...@merkleinc.com<mailto:j...@merkleinc.com>> wrote: Is there a way to read Hive Map datatype without knowing keys? According to Hive document, the only way to read a Map is to access through keys, ie: myMap['myKey']. However, in many cases, the keys are unknown, for example, HTable sparse columns, so in that kind of situation, what is the ways to read the map?
