Question

MySQL查询语句

我现在有一张表--tb_DM_Demand,表里有两个字段(DemandNO,RequireQty), 我希望从另外两张表查询数据,一张tb_DM_Deduction,一张tb_IM_Interview,这两张表都含有一个字段(DemandNO)与tb_DM_Demand的字段(DemandNO)是有关联的.我希望通过一条SQL语句查询出,DemandNO 在tb_DM_Deduction表和在tb_IM_Interview表的总数,期望得到图2的结果,详见图:

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Answer 1

SELECT a.DemandNO,IFNULL(countb,0)+IFNULL(countc,0) as 结果  from tb_dm_demand a LEFT JOIN

(SELECT DemandNO,COUNT(1) as countb from tb_dm_deduction GROUP BY DemandNO) b 

ON a.DemandNO=b.DemandNO LEFT JOIN

(SELECT DemandNO,COUNT(1) as countc from tb_im_interview GROUP BY DemandNO) c

ON a.DemandNO=c.DemandNO ORDER BY DemandNO

Answer 2

网页链接MySQL查询语句可以访问此网址

Answer 3

表达不清楚啊 你把表字段贴出来了啊