Would you expect coalesce to return a result when none of the columns in coalesce exist in the parquet file ??
Query 1: select coalesce(cert_statusdd,cert_status33) from dfs.`/tmp/parquetfiles`; Error: SYSTEM ERROR: CompileException: Line 56, Column 27: Assignment conversion not possible from type “org.apache.drill.exec.expr.holders.NullableIntHolder” to type “org.apache.drill.exec.vector.UntypedNullHolder” Fragment 1:0 [Error Id: 7b9193fb-289b-4fbf-a52a-2b93b01f0cd0 on dkvm2c:31010] (state=,code=0) In above case both the columns do not exist. Is the error reported a valid error or is it a bug. Another observation is that if you use CAST on the column that does not exist, Coalesce will not error out instead return nulls. Query 2: select coalesce(cast(cert_statusdd as varchar),cast(cert_statusee as varchar)) from dfs.`/tmp/parquetfiles` limit 3; +---------+ | EXPR$0 | +---------+ | null | | null | | null | +————+ Note: Databases like postgresql and mysql will not allow COALESCE on non existing column, w or without CAST. Drill however being schema free, do we expect COALESCE to succeed and give null as result ?? In which case the SYSTEM ERROR: CompileException with the 1st Quert be a bug. ?? Thanks. - Deepak ([email protected] <mailto:[email protected]>)
