Hi, Hyde:
It's confused me that some annotations in
Calcite(org.apache.calcite.sql.fun.SqlGroupingFunction.java) :
/**
* The {@code GROUPING} function.
*
* <p>Accepts 1 or more arguments.
* Example: {@code GROUPING(deptno, gender)} returns
* 3 if both deptno and gender are being grouped,
* 2 if only deptno is being grouped,
* 1 if only gender is being groped,
* 0 if neither deptno nor gender are being grouped.
*
* <p>This function is defined in the SQL standard.
* {@code GROUPING_ID} is a non-standard synonym.
*
* <p>Some examples are in {@code agg.iq}.
*/
The annotations above seems conflicts with other implementations like Hive(
https://cwiki.apache.org/confluence/display/Hive/Enhanced+Aggregation%2C+Cube%2C+Grouping+and+Rollup?spm=ata.13261165.0.0.528c6dfcXalQFy#EnhancedAggregation,Cube,GroupingandRollup-Groupingfunction
)
Notice that: "The grouping function indicates whether an expression in a
GROUP BY clause is aggregated or not for a given row. The value 0
represents a column that is part of the grouping set, while the value 1
represents a column that is not part of the grouping set. "
It is clearly that 0 and 1 bit have different interpretation between
annotations in Calcite and in Hive. And I did not figure out why...
Any feedback can give me on this would be highly appreciated.
Best regards!
