联合查询更新表数据

Sql Server

1 UPDATE a SET WtNo=b.NO
2 from WT_Task a
3 INNER JOIN WT_BasicInformation b ON a.WtId=b.ID;

或者

1 update a set a.ProjectID=b.ProjectID from
2 [ICTR_Project_NoticeSubkey] a,[iCTR_Project_Projects] b 
3 where a.ParentProjectID=b.ParentProjectID
4 and a.zt=2

My Sql

 1 # update select 语句(注意:必须使用inner join)
 2 # 语法 update a inner join (select yy from b) c on a.id =c.id set a.xx = c.yy
 3 #SELECT knowledge_id,COUNT(0) nums FROM pro_base_timu_knowledge GROUP BY knowledge_id;
 4 UPDATE pro_base_knowledge
 5 INNER JOIN (
 6 SELECT
 7 knowledge_id,
 8 COUNT(0) nums
 9 FROM
10 pro_base_timu_knowledge
11 GROUP BY
12 knowledge_id
13 ) b ON pro_base_knowledge.id = b.knowledge_id
14 SET pro_base_knowledge.timu_num = b.nums