A Data Manager Data Adapter using JDBC to connect to MySQL will not return any data if column name aliases are used on returned fields where no operation is performed:
a.sample_time as timekey, -- BAD
(a.usr + a.sys) as CPU_Util, -- GOOD
a.mem_pct as MEM_Util -- BAD
from source_table a
where ... ;
Data will likely be returned in the SQL development tool being used to build the query, but when embedded in Data Manager, a Staging job will return 'No Data found for time range ...' errors.
The reason is because the JDBC connection does not update the column names to the alias if no operation is performed on the source column.
a.sample_time, -- GOOD
a.mem_pct -- GOOD
concat(a.sample_time,'') as timekey, -- GOOD
(a.mem_pct + 0.0) as MEM_Util -- GOOD