[teiid-issues] [JBoss JIRA] (TEIID-3794) Impala Count Distinct with Case Statement Generates Bad SQL

Impala Count Distinct with Case Statement Generates Bad SQL ----------------------------------------------------------- Key: TEIID-3794 URL: https://issues.jboss.org/browse/TEIID-3794 Project: Teiid Issue Type: Feature Request Components: Misc. Connectors Affects Versions: 8.12 Reporter: Scott Wallace Assignee: Steven Hawkins Executing a query like: {noformat} select count(distinct case when string_column='X' then bigint_column end) from some_vdb {noformat} Translates as the following in Impala: {noformat} SELECT COUNT(DISTINCT (CASE WHEN (`string_column` = 'X') THEN `bigint_column` ELSE CAST(NULL AS STRING) END)) as `EXPR_0` FROM `some_table` {noformat} Which fails with the following error: {noformat} AnalysisException: Incompatible return types 'BIGINT' and 'STRING' of exprs 'integer_column' and 'CAST(NULL AS STRING)'. {noformat}