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摘要: left join 和 left outer join 的区别通俗的讲:AleftjoinB的连接的记录数与A表的记录数同ArightjoinB的连接的记录数与B表的记录数同AleftjoinB等价BrightjoinAtableA:Field_K,Field_A1a3b4ctableB:Field_K,Field_B1x2y4zselecta.Field_K,a.Field_A,b.Field_K,b.Field_Bfromaleftjoinbona.Field_K=b.Field_KField_KField_AField_KField_B-------------------------- 阅读全文
posted @ 2012-06-15 18:12 草莓在努力 阅读(333) 评论(0) 推荐(0) 编辑