When there are multiple possible sources in a query, only PTI tables are considered when Teradata Database is inferring the timecode column. The TD_TIMECODE column is inferred by Teradata Database only when it is not ambiguous.
Example: Multiple Sources in a Query
In the example only ocean_buoys is considered when inferring the timecode, so no USING TIMECODE clause is necessary.
sel avg(a.temperature), mode(b.temperature) from ocean_buoys a inner join ocean_buoys_nonpti b on a.buoyid = b.buoyid group by time(minutes(10));
Example: Invalid Example with Ambiguous Timecode Specification
In the example, TD_TIMECODE is ambiguous so it cannot be inferred and an error is reported. Because both join tables have TD_TIMECODE, USING TIMECODE is required to specify which TD_TIMECODE to use.
sel avg(a.temperature), mode(b.temperature) from ocean_buoys a inner join ocean_buoys_seq b on a.buoyid = b.buoyid group by time(minutes(10)); *** Failure 4359 Time Series: Timecode specification is ambiguous.