SELECT * from A inner join (select prj_id,(counts_1 * Unit_Price_1)+(counts_2 * Unit_Price_2)+(counts_3 * Unit_Price_3)+(counts_4 * Unit_Price_4) as sum_count from A) B on A.Prj_ID=B.Prj_ID
SELECT * from A inner join (select prj_id,(counts_1 * Unit_Price_1)+(counts_2 * Unit_Price_2)+(counts_3 * Unit_Price_3)+(counts_4 * Unit_Price_4) as sum_count from A) B on A.Prj_ID=B.Prj_ID 求助,上面SQL中计算的字段如果为空则将字段赋值为0,这个sql如何写?? access中能写函数吗?