Question

memsql中不是不支持多表查询，但是我想实现将一张表的字段赋值给另外一张表的字段

如何在memsql中实现update B set extra = A.extra from A join B on (A.id = B.id);，高手大侠快来帮帮我吧！万分感谢
是否可以写个存储过程，谁会写帮我一下，谢谢！两张表的表名需要是参数传入！

Answer 1

update B set extra=(select extra from A where id=B.id)

追问

ERROR 1749 (HY000): Feature 'Correlated subselect that can not be transformed and does not match on shard keys' is not supported by MemSQL Distributed. 不支持

追答

那抱歉了，

追问

没事，谢谢！存储过程是否可以解决呢

追答

存储过程，写循环可以一条条处理，但是很无语，应该有简单方法

追问

那你能帮我写个存储过程吗？谢谢啦！

追答

declare @id int,@extra varchar(20)
DECLARE cur CURSOR FOR
select extra ,id from A
OPEN cur
FETCH NEXT FROM cur INTO @extra,@id
WHILE (@@FETCH_STATUS=0)
BEGIN
update B set extra= @extra where id= @id
FETCH NEXT FROM cur INTO @extra,@id
END
CLOSE cur
DEALLOCATE cur