程晓晖

摘要： SELECT * FROM test1 as t1 left join test2 as t2 on t1.ida=t2.aid --and t2.bid>2执行结果1 1 1 51 1 1 62 2 2 22 2 2 33 3 NULL NULL4 4 NULL NULL5 5 NULL NULLSELECT * FROM test1 as t1 left join test2 as t2 on t1.ida=t2.aid and t2.bid>21 1 1 51 1 1 62 2 2 33 3 NULL NULL4 4 NULL NULL5 5 NULL NULL即left j 阅读全文