This example shows how when an expanded column is not specified in the select list of a query, but a DISTINCT operator is specified, the EXPAND operation is nullified.
CREATE SET TABLE df2.t1, NO FALLBACK, NO BEFORE JOURNAL, NO AFTER JOURNAL, CHECKSUM = DEFAULT, DEFAULT MERGEBLOCKRATIO ( i INTEGER, j INTEGER, pd PERIOD(DATE) FORMAT 'yyyy-mm-dd') PRIMARY INDEX (i);
The first SELECT statement in this example does not specify the DISTINCT operator.
EXPLAIN SELECT i,j FROM t1 EXPAND ON pd AS expd BY INTERVAL '1' DAY;
An EXPLAIN shows an EXPAND ON t1.pd.
The following SELECT statement specifies the DISTINCT operator.
SELECT DISTINCT i,j FROM t1 EXPAND ON pd AS expd BY INTERVAL '1' day;
An EXPLAIN shows a SORT and elimination of duplicate rows. The DISTINCT operator makes the EXPAND ON step unnecessary.