继续获取“cursor is READ-ONLY”

Question

我的代码看起来很前卫。

我想用唯一的计数器更新一个特定的字段，不等于{1,2,3，...}。

我一直收到错误“游标是只读的”。

还有:有没有更简单的方法？

declare @MaxVal int = NULL
declare @fetchVal int = NULL
select @MaxVal = MAX(tp_Id)+1 from [<tableContainingInitialMaxval>] 
/** some default **/

DECLARE curs01 CURSOR 
for select @maxVal + row_number() OVER (order by [<someUniqueField>]) from [<table2update>];
(used FOR UPDATE OF [<field2update>] but that made no difference)

open curs01
FETCH NEXT FROM curs01 INTO @fetchVal;
WHILE @@FETCH_STATUS = 0
    begin
        update [<table2update>] set [<field2update>] =  @fetchVal 
        WHERE CURRENT OF curs01;
        FETCH NEXT FROM curs01 INTO @fetchVal;
    end;
CLOSE curs01;
DEALLOCATE curs01;
GO 

Answer 1

你不需要一个游标来做这个。

DECLARE @MaxVal INT = NULL

SELECT @MaxVal = MAX(tp_Id) + 1
FROM   tableContainingInitialMaxval;

WITH CTE
     AS (SELECT *,
                @maxVal + row_number() OVER (ORDER BY someUniqueField) AS rn
         FROM   table2update)
UPDATE CTE
SET    field2update = rn