为什么这个非常简单的光标会破坏 SQL Server Management Studio？

Question

我在学位 table 上创建了一个项目，我想为其他 19 个学院复制该记录。我有一个非常简单的游标，但每次我运行它都会完全崩溃 SQL Server Management Studio。有没有办法重写此查询（或完全执行相同 INSERT INTO 的另一个查询），使其不会崩溃（并实际执行）？

DECLARE @Colleges VARCHAR(200)

DECLARE DUPLICATE_DEGREE CURSOR FOR
SELECT CollegeID FROM Colleges WHERE CollegeName <> 'Main Office'
OPEN DUPLICATE_DEGREE 
FETCH NEXT FROM DUPLICATE_DEGREE INTO @Colleges

WHILE @@FETCH_STATUS = 0
BEGIN

INSERT INTO Degree
(
  DegreeName
, CollegeID
)
SELECT
  DegreeName
, @Colleges
FROM Degrees
WHERE DegreeID = 123

END

CLOSE DUPLICATE_DEGREE 
DEALLOCATE DUPLICATE_DEGREE

Answer 1

您的脚本陷入无限循环，因为您永远不会前进光标，因此 @@FETCH_STATUS 的值永远不会改变，导致您为同一所大学添加相同的记录，令人作呕。在 INSERT.

后添加 FETCH NEXT FROM DUPLICATE_DEGREE INTO @Colleges

Answer 2

Jake - 你不需要光标，试试这个：

DECLARE @DegreeName varchar (256)
SET @DegreeName = SELECT DISTINCT DegreeName from Degrees WHERE DegreeID = 123

INSERT INTO Degree (DegreeName, CollegeID) 
   SELECT @DegreeName, CollegeID 
   FROM Colleges WHERE CollegeName <> 'Main Office'

为什么这个非常简单的光标会破坏 SQL Server Management Studio？

Why is this very simple cursor breaking SQL Server Management Studio?

sql-server

database-cursor