摘要： EG1:通俗的讲A left join B 的连接的记录数与A表的记录数同A right join B 的连接的记录数与B表的记录数同 A left join B 等价B right join Atable A:Field_K, Field_A1 a3 b4 ctable B:Field_K, Field_B1 x2 y4 zselect a.Field_K, a.Field_A, b.Field_K, b.Field_Bfrom a left join b on a.Field_K=b.Field_KField_K Field_A Field_K Field_B ---------- --- 阅读全文