sql-server - 持续获取“光标为只读”

我的代码似乎很向前。

我想使用唯一计数器（不等于{1,2,3，...}）更新特定字段。

我不断收到错误消息“光标仅可读”。

另外：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

最佳答案

您不需要为此的光标。

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

maxval

sql-server - 持续获取“光标为只读”