求差集：表1-表2的差

求差集：表1-表2的差

#方法1

SELECT t1.id t1d,t2.id t2d

FROM lishi_sports_data_copy20170817 t1 LEFT JOIN lishi_sports_copy20170817 t2 ON t1.id = t2.id

WHERE  t2.id is NULL;

#方法2

SELECT lishi_sports_data_copy20170817.id from lishi_sports_data_copy20170817 where  not EXISTS(SELECT lishi_sports_copy20170817.id from lishi_sports_copy20170817 where lishi_sports_copy20170817.id = lishi_sports_data_copy20170817.id);