Please try the following two options. Option 2 might be better, performance wise (depending of the data volume and characteristics).
P.s. I didn’t understand the explanation about the LEFT JOIN Dudu 1. select b.code ,b.value from b left join a on a.type = b.type and a.code like case b.code when 'ALL' then '%' else b.code end and a.indicator like case b.indicatior when 'ALL' then '%' else b.indicatior end ; 2. select b.code ,b.value from b left join a on a.type = b.type and a.code = b.code and a.indicator = b.indicatior where b.code != 'ALL' and b.indicatior != 'ALL' union all select b.code ,b.value from b left join a on a.type = b.type and a.indicator = b.indicatior where b.code = 'ALL' and b.indicatior != 'ALL' union all select b.code ,b.value from b left join a on a.type = b.type and a.code = b.code where b.code != 'ALL' and b.indicatior = 'ALL' union all select b.code ,b.value from b left join a on a.type = b.type where b.code = 'ALL' and b.indicatior = 'ALL' ; From: Kishore A [mailto:kishore.atmak...@gmail.com] Sent: Tuesday, April 19, 2016 3:51 PM To: user@hive.apache.org Subject: Re: Question on Implementing CASE in Hive Join Hi Dudu, Actually we use both fields from left and right tables, I mentioned right table just for my convenience to check whether ALL from right table can be pulled as per join condition match. One more reason why we use left join is we should not have extra columns after join. Kishore On Tue, Apr 19, 2016 at 5:46 AM, Markovitz, Dudu <dmarkov...@paypal.com<mailto:dmarkov...@paypal.com>> wrote: Before dealing with the technical aspect, can you please explain what is the point of using LEFT JOIN without selecting any field from table A? Thanks Dudu From: Kishore A [mailto:kishore.atmak...@gmail.com<mailto:kishore.atmak...@gmail.com>] Sent: Tuesday, April 19, 2016 2:29 PM To: user@hive.apache.org<mailto:user@hive.apache.org> Subject: Question on Implementing CASE in Hive Join Hi, I have a scenario to implement to cases in Hive Joins. I need to implement case on the value on which join condition to be applied. Table A Code// Type// Indicator// Value// A 1 XYZ John B 1 PQR Smith C 2 XYZ John C 2 PQR Smith D 3 PQR Smith E 3 XYZ Smith F 4 MNO Smith G 3 MNO Smith D 1 XYZ John N 3 STR Smith Table B Code// Type// Indicator// Value// ALL 1 XYZ John D 3 ALL Smith ALL 1 PQR Smith I need to stamp Value from TableB by joining TableA and I am writing join condition as below. Note : No instance of ALL for Type column, a value for Type will be provided. Select b.Code,b.Value from B LEFT JOIN A a ON a.Code = (case when b.Code = 'ALL' then a.Code else b.Code END) AND a.Type = b.Type AND a.Indicator = (case when b.Indicatior = 'ALL' then a.Inidicator else b.Inidicator END) When I run this in hive this query is failing with below error Error while compiling statement: FAILED: SemanticException [Error 10017]: Line 4:0 Both left and right aliases encountered in JOIN 'Code'. Please let me know if more details are needed Thanks, Kishore