Differences between two oracle query tables

Differences between two oracle query tables oracle query two table differences such as table 1 create table T1 (MAC VARCHAR2 (150), PURCHASENAME VARCHAR2 (200), PRODUCTID VARCHAR2 (200 )) table 2 create table T2 (MACADDR VARCHAR2 (20), PRODUCTID VARCHAR2 (20) records in table 1: mac purchaname productid 456521524 test1 A3_3445 456521524 test2 A3_3424 456521524 test2 A3_1254 Table 2 record macaddr proucutid 456521524 A3_3445 456521524 A3_3424 use the keyword minus to query the differences between two tables select * from T1 minus select * by 2 desc; 2 is the 2nd column in the query table.