Oracle's minus returns data from the first table that is not in the second table

Oracle's minus returns data from the first table that is not in the second table

CREATE TABLEhovertree_union_1 (IDINT, ValVARCHAR(Ten)  ); CREATE TABLEhovertree_union_2 (IDINT, ValVARCHAR(Ten)  ); INSERT  intoHovertree_union_1VALUES(1,'A'); INSERT  intoHovertree_union_1VALUES(2,'B'); INSERT  intoHovertree_union_1VALUES(3,'C'); INSERT  intoHovertree_union_2VALUES(1,'A'); INSERT  intoHovertree_union_2VALUES(1,'A'); INSERT  intoHovertree_union_2VALUES(2,'B'); INSERT  intoHovertree_union_2VALUES(4,'D'); SQL> SELECT *  fromhovertree_union_12minus3 SELECT *  fromhovertree_union_2; ID VAL---------- --------------------  3C SQL> SELECT *  fromhovertree_union_22minus3 SELECT *  fromhovertree_union_1; ID VAL---------- --------------------  4D--how to ask Hovertree.com

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Oracle minus returns data from the first table that is not in the second table