使用子查詢和連接進行更新

Question

如何使用此查詢的結果更新table1 -

select b.description from 
table1 c
join 
(
    SELECT distinct a.hcpc, a.description
    FROM table2 a 
) b 
on b.hcpc = c.hcpc
where c.description = '0'

我想做這樣的事情-

update table1 
set table1.description = (select b.description from table1 c
join 
(
    SELECT distinct a.hcpc, a.description
    FROM table2 a 
) b 
on b.hcpc = c.hcpc
where c.description = '0'
) 

Answer 1

這個問題已經在SO中回答了很多次......無論如何，查詢應該以這種方式構建

一種選擇

update table1 c
set description = b.description
from
  (
    SELECT distinct a.hcpc, a.description
    FROM table2 a 
  ) b  
where b.hcpc = c.hcpc
  and c.description = '0'

其他選項

with t as (
  SELECT distinct a.hcpc, a.description
  FROM table2 a
)
update table1 c
set description = t.description
from t
where t.hcpc = c.hcpc
  and c.description = '0'

當然還有其他的方法...