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这样不行?
update ryb set bz='最长'
where len(sm)=
(select top 1 MAX(len (sm)) from ryb)
update ryb set bz='最长' from(
select top 1 * from ryb where xm='张三' order by len(sm) desc) as b where ryb.xm=b.xm and ryb.sm=b.sm
create table ryb (nam varchar(10),bz varchar(10),sm varchar(20))
insert into ryb
select '张三' as name,null as bz,'你好' as sm union all
select '李四',null,'啊好吗'
update ryb set bz='最长'
where LEN(sm)=(select MAX(len(sm)) from ryb)
--结果
nam bz sm
---------- ---------- --------------------
张三 NULL 你好
李四 最长 啊好吗
(2 行受影响)
update a
set a.bz='最长'
from ryb a inner join (select xm,max(sm)sm
from ryb
group by xm) b on a.xm=b.xm and a.sm=b.sm
select top 1 * from ryb where xm='张三' order by len(sm) desc
UPDATE ryb SET 字段=‘’
where bz=
(SELECT TOP 1 bz FROM PRDT ORDER BY LEN(bz) DESC))
UPDATE ryb SET 字段=‘’
where bz=
(SELECT TOP 1 bz FROM PRDT ORDER BY LEN(NAME) DESC))