Question

使用此查询我需要SQL做的是根据另一列更新列值，以便它获取最新的MAX ID。

select 
    max(T1id), t1.v_code 
from 
    [Table1] T1
join 
    [Table2] t2 on t1.T1Code = t2.T2Code
where 
    t2.active = 0
    and t1.t1activesw = 0
    and t1.mapping not like '%selected%'
group by 
    t1.v_code

我想在版本代码id = max（t1.v_code）上加入select到表格，然后将代码用作子选择而不确定如何完成它。

Answer 1

通过这个，您可以从行中获取每个T1.v_code的最高T1.id的所有数据：

;WITH CTE as
(
  SELECT
      T1.*, 
      row_number() over (partition by T1.v_code order by T1.id desc) rn
  FROM
      [Table1] T1
  JOIN
    [Table2] t2 on t1.T1Code = t2.T2Code
  WHERE
    t2.active = 0
    and t1.t1activesw = 0
    and t1.mapping not like '%selected%'
)
SELECT * 
FROM CTE 
WHERE rn = 1

编辑：为了更新，替换（按照通知中的要求）

SELECT * 
FROM CTE 
WHERE rn = 1

带

UPDATE CTE 
SET columnname = 'newvalue' 
WHERE rn = 1

此

T SQL使用max函数更新行

1 个答案: