尝试这样的事情：

  UPDATE  t1  SET  t1.sal = t2.sal 
 FROM  \\ temp  AS  t1  INNER   JOIN （
 SELECT  id， CASE   WHEN  dep = '  it' 那么 sal + 1000 
 WHEN  dep = '  ac'  THEN  sal + 2000 
 ELSE  sal 
 END   AS  sal 
 FROM  emp 
） AS  t2  ON  t1.id = t2.id 

  update  \\ temp  set  sal = sal + 
（ 
 case  何时 dep = ' 它' 然后  1000  
当 dep = '  ac' 然后  2000  
 else   0  
 end  
）

  update  emp e1  set  e1.sal = e1.sal +（ select   case  当 e1.dep = '  it'   '  1000' 
 when  e1.dep = '  ac'  then  '  2000' 
 else  '  0' 
端跨度>）

ID   NAME              SAL    DEP   LOC
----  ------ ---------- ---------- ----- -----
  1   viki              1000   it    cb
  2   allen             2000   ac    ch
  3   smith             2000   ac    sa
  4   adam              5000   it    ch
  5   will              4000   ac    cb
  6   john              6000   it    cb
  7   bradley          10000   it    ch

i have table like this if dep = 'it' update 1000 if dep='ac' update 2000


I tried this query but it fails

update emp set sal=sal+(select case when dep='it' then '1000'
                                    when dep='ac' then '2000'
                                    else '0'
                                    end
                                    from emp);

Try something like this:

UPDATE t1 SET t1.sal = t2.sal
FROM emp AS t1 INNER JOIN (
    SELECT id, CASE WHEN dep='it' THEN sal+1000
                   WHEN dep='ac' THEN sal+2000
                   ELSE sal
               END AS sal
    FROM emp
    ) AS t2 ON t1.id = t2.id

update emp set sal=sal+
(
  case when dep='it' then 1000
       when dep='ac' then 2000
       else 0
       end
)

update emp e1 set e1.sal=e1.sal + (select case when e1.dep='it' then '1000'
                                    when e1.dep='ac' then '2000'
                                    else '0'
                                    end)